The acute effect of strength exercises at different intensities on intraocular pressure

Acute Effects of Resistance Exercise on Intraocular Pressure in Healthy Adults: A Systematic Review

ABSTRACT

Hackett, DA, Li, J, Wang, B, Way, KL, Cross, T, and Tran, DL. Acute effects of resistance exercise on intraocular pressure in healthy adults: A systematic review. J Strength Cond Res 38(2): 394-404, 2024-Intraocular pressure (IOP) tends to fluctuate during a resistance exercise (RE). This systematic review examines the acute effects of RE on IOP in healthy adults and factors that influence changes in IOP. Five electronic databases were searched using terms related to RE and IOP. A strict inclusion criterion was applied, which included being 55 years or younger with no medical conditions and RE intensity needing to be quantifiable (e.g., based on a maximal effort). Thirty-four studies met the inclusion criteria for this review. Isometric and isotonic contractions produced similar changes in IOP during RE up to 28.7 mm Hg. Exercises that involved larger muscle mass, such as squats and leg press, were found to produce changes in IOP during exercise ranging from 3.1 to 28.7 mm Hg. Smaller changes in IOP during RE were found for exercises engaging less muscle mass (e.g., handgrip and bicep curls). Intraocular pressure was found to increase during RE when lifting heavier loads and with longer exercise durations (e.g., greater repetitions). The Valsalva maneuver (VM) and breath-hold during RE accentuated the change in IOP, with more extreme changes observed with the VM. However, most studies showed that postexercise IOP returned to baseline after approximately 1 minute of recovery. An acute increase in IOP is observed during RE in healthy adults with fluctuations of varying magnitude. Factors that independently increase IOP during RE include exercises involving larger muscle mass, heavy loads, greater set duration, and when the VM or breath-hold is performed.

Effect of Different Postures on Intraocular Pressure in Open-Angle Glaucoma

INTRODUCTION

This study aims to investigate the pattern of intraocular pressure (IOP) changes in different postures among patients with open-angle glaucoma (OAG).

METHODS

A observational study was conducted on a total of 74 patients with OAG (148 eyes). IOP measurements were taken in a variety of positions, including supine, left lateral decubitus, right lateral decubitus, head tilted downwards position with immediate head-up (transient head tilted downwards), seated, seated with head tilted downwards, standing, and walking. Each position was held for 5 min before measurement. In all positions, the patient maintains both eyes looking forward and remains alert. In the head tilted downwards position, the angle of head tilt with respect to the sagittal plane was 30°.

RESULTS

The overall trend of IOP changes showed a significant decrease with an increase in the position height (r = 0.037, p < 0.001). The IOP was significantly higher in the supine, left lateral decubitus, right lateral decubitus, and head tilted downwards positions than in the seated position (p < 0.001). Compared with the seated position with eyes at primary gaze, IOP decreased significantly when standing (p = 0.008) or walking (p < 0.001). The IOP in the left lateral decubitus and right lateral decubitus was significantly higher than in the supine position (p = 0.008, p = 0.001, respectively). The IOP decreased significantly during walking compared with standing (p < 0.001).

CONCLUSIONS

The magnitude of IOP strongly correlates with the body position during IOP measurement. The head tilted downwards, supine, left lateral decubitus, and right lateral decubitus positions result in a higher IOP than IOP at the seated position. Patients with OAG can potentially reduce IOP fluctuations by adjusting their daily postures.

Acute Intraocular Pressure Responses to Resistance Training in Combination With Blood Flow Restriction

Objective: To determine the effect of blood flow restriction (BFR) applied to the legs at different pressures (40% and 60%) on intraocular pressure (IOP) during the execution of ten repetitions maximum (10RM) in the half-squat exercise. Methods: Quasi-experimental, prospective study with 17 healthy physically active subjects (9 males and 8 females; 24.1 ± 4.2 years). Two sessions were conducted. The 10RM load was determined in the first session. The second session consisted of 10RM under three BFR conditions (no-BFR, 40%-BFR, and 60%-BFR) that were applied in random order. IOP was measured before each condition, immediately after each repetition, and after 1 minute of passive recovery. A two-way repeated-measures ANOVA (restriction type [no-BFR, 40%-BFR, and 60%-BFR] x measurement point [basal, repetitions 1-10, and recovery]) was applied on the IOP measurements. Results: A significant main effect of the BFR condition (p = .022, ƞp2 = 0.21) was observed due to the significantly higher mean IOP values for the 60%-BFR (19.0 ± 0.7 mmHg) compared to the no-BFR (18.0 ± 0.8 mmHg; p = .048, dunb = 1.30). Non-significant differences with a large effect size were reached between 60%-BFR and 40%-BFR (18.1 ± 0.8 mmHg; p = .081, dunb = 1.16) and between no-BFR and 40%-BFR (p = .686, dunb = 0.18). IOP increased approximately 3-4 mmHg from baseline to the last repetition. Conclusions: Low-pressure BFR (40%-BFR) in combination with moderate-load (10RM load) resistance exercise could be an effective and safe strength training strategy while avoiding IOP peaks associated with heavy-load resistance exercises. These findings incorporate novel insights into the most effective exercise strategies in individuals who need to maintain stable IOP levels (e.g., glaucoma patients).

Influence of the body positions adopted for resistance training on intraocular pressure: a comparison between the supine and seated positions

OBJECTIVES

A variety of factors are known to mediate on the intraocular pressure (IOP) response to resistance training. However, the influence of the body position adopted during resistance training on IOP remain unknown. The objective of this study was to determine the IOP response to the bench press exercise at three levels of intensity when performed in supine and seated positions.

METHODS

Twenty-three physically active healthy young adults (10 men and 13 women) performed 6 sets of 10 repetitions against the 10-RM (repetition maximum) load during the bench press exercise against three levels of intensity (high intensity: 10-RM load; medium intensity: 50% of the 10-RM load; and control: no external load) and while adopting two different body positions (supine and seated). A rebound tonometer was employed to measure IOP in baseline conditions (after 60 s in the corresponding body position), after each of the 10 repetitions, and after 10 s of recovery.

RESULTS

The body position adopted during the execution of the bench press exercise significantly affected the changes in IOP (p < 0.001, η_p² = 0.83), with the seated position providing lower increases in IOP levels compared to the supine position. There was an association between IOP and exercise intensity, with greater IOP values in the more physically demanding conditions (p < 0.001, η_p² = 0.80).

CONCLUSIONS

The use of seated positions, instead of supine positions, for the execution of resistance training should be prioritized for maintaining more stable IOP levels. This set of findings incorporates novel insights into the mediating factors on the IOP response to resistance training. In future studies, the inclusion of glaucoma patients would allow to assess the generalizability of these findings.

Effect of Aerobic Exercise at Different Intensities on Intraocular Pressure in Young Males

PRCIS

High intensity aerobic exercise significantly reduced intraocular pressure in healthy young male adults.

OBJECTIVE

This study sought to determine how aerobic exercise at various intensities affects intraocular pressure (IOP) in young adults.

DESIGN

A repeated measures design was adopted.

PARTICIPANTS

A group of 20 volunteers (mean age: 21.24±1.73 y) took part in this study.

METHODS

IOP was measured with a tonometer (iCare TA01i, Icare Finland, Finland). Subjects completed 4 cycle ergometer sessions. During the first session, power was increased by 60 W every 3 minutes until exhaustion, corresponding to peak power. For the 3 following tests, each lasting 25 minutes, subjects exercised at intensities of 50%, 70%, and 85% of peak power, respectively, and measurements were taken every 5 minutes.

MAIN OUTCOME MEASURES

IOP, as determined using a tonometer, was the primary measure.

RESULTS

There was a significant reduction ( P <0.05) in IOP of both eyes during the 25 minutes high-intensity (85%) exercise test. There were also significant interactions between exercise durations and intensities. During high-intensity exercise, IOP, blood pressure, blood lactate, and the rating of perceived exertion were significantly related ( P <0.01).

CONCLUSIONS

These data show a significant reduction in IOP at high-intensity aerobic exercise, which may have implications for the management of ocular health.

Effect of wearing different types of face masks during dynamic and isometric resistance training on intraocular pressure

CLINICAL RELEVANCE

The use of face masks has demonstrated to be an effective strategy to prevent transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Wearing face masks, mainly Filtering Face Piece 2 (FFP2) masks, during exercise practice has demonstrated to affect several physiological measures.

BACKGROUND

This study was aimed at assessing the intraocular pressure (IOP) behaviour during the execution of the dynamic and isometric biceps-curl exercise with a surgical and FFP2 face mask.

METHODS

Twenty two physically active young adults performed sets of 10 repetitions against the 10-RM (repetition maximum) load and 1-minute isometric effort against a load 15% lower than the 10-RM load with the FFP2 and surgical mask and without any mask. A total of six exercise sets (3 experimental conditions [FFP2, surgical and control] × 2 exercise modalities) were performed. A rebound tonometer was used to measure IOP before, during (10 measurements), and after (30-seconds of passive recovery) each training set.

RESULTS

At rest, there were not statistically significant IOP differences (p = 0.222). During dynamic exercise, there was a progressive IOP rise (p < 0.001), and a higher IOP response with the FFP2 than without the mask (corrected p-value = 0.003). For the isometric exercise, there was a greater IOP response as a function of accumulated effort (p < 0.001), which was dependent of the face mask used (FFP2> surgical>control; corrected p-values< 0.01).

CONCLUSIONS

The FFP2 masks cause a heightened IOP response during the execution of dynamic and isometric biceps-curl exercise, suggesting that, when possible, glaucoma patients should limit the use of FFP2 masks during resistance training.

Physical Activity Is Associated with Improved Visuomotor Processing in Older Adults with Moderate and Advanced Glaucomatous Visual Field Defect: A Cross-Sectional Study

Glaucoma affects a wide spectrum of daily essential activities in older adults. This study examined whether older adults with moderate and advanced stages of glaucoma exhibit differences in visuomotor task performance compared with age- and gender-matched ophthalmologically healthy control subjects and estimated the effects of physical activity (PA) levels, age, and severity of visual impairment on patients' visuomotor task performance. Sixty older adults with moderate glaucoma, advanced glaucoma, and normal sight participated in the study. Visuomotor processing was assessed using laboratory-based simple and complex visuomotor reaction tasks. Monocular Humphrey Visual Field and binocular Humphrey Esterman Visual Field tests were used to estimate visual field defect severity. The International Physical Activity Questionnaire was used to assess PA levels. Participants with glaucoma had poorer scores in visuomotor tasks compared to participants with normal sight. Glaucoma patients' PA levels, age, and binocular visual field defect explained 54% of the variation in complex reaction time. Low PA levels were identified as a risk factor for visuomotor processing decline. Compensatory mechanisms to improve the efficiency of visual field scanning in patients with more severe visual field defects may exist.

Therapeutic and preventive eff ect of physical exercises in primary open-angle glaucoma

The review assesses physical exercises as an additional non-pharmacological mean of combating the progression of primary open-angle glaucoma. The ophthalmic hypotensive effect is determined by the type of exercise, its duration and intensity. Moderate aerobic activity is preferred. Among dynamic exercises, jogging has the greatest hypotensive effect. Upper body isometric resistance training provides a more lasting decrease in ophthalmotonus. The decrease in intraocular pressure (IOP) in patients with glaucoma is several times more pronounced in comparison with healthy people and occurs regardless of the nature of the local drug antihypertensive therapy. After the termination of classes IOP returns to the previous level on average within a month. An increase in ocular perfusion pressure associated with physical activity dictates the appropriateness of physical exercise for patients with pseudo-normal pressure glaucoma. The combination of hypotensive, vascular, neuroprotective effects of physical activity with a high level of physical fi tness does not exclude a decrease in the risk of development and progression of primary open-angle glaucoma. The development of indications for the use of physical activity by patients with advanced glaucoma, including those who have undergone hypotensive surgery, remains relevant. The type, intensity, dosage and mode of performing the recommended physical exercises require an individual choice.

Do Age and Sex Play a Role in the Intraocular Pressure Changes after Acrobatic Gymnastics?

To evaluate the effects of an acrobatic gymnastics (AG) training session on intraocular pressure (IOP), a familiarization session was employed to confirm the participant's suitability for the study. Forty-nine gymnasts (63.27% females, 18-40 years old) voluntarily agreed to participate. As age, sex, baseline IOP, and central corneal thickness (CCT) were considered as potential predictors of the IOP variations, in the second session measurements of the above parameters were taken before and after 90 min of AG. A mixed-factorial analysis of variance evaluated differences. Linear regression was conducted to potentially predict the IOP variation with the exercise. After the scheduled exercise, highly significant (p < 0.001, effect size: 0.73) reductions in IOP, but no significant changes in CCT (p = 0.229), were observed. IOP was significantly modified in males, older than 25 years, and subjects with baseline IOP > 14 mmHg (p ≤ 0.001, effect sizes: 0.57-1.02). In contrast, the IOP of females, younger participants, and subjects with baseline IOP ≤ 14 mmHg was not significantly modified (p = 0.114). With the regression analyses, we concluded that both sex and baseline IOP levels were significant predictors of the IOP fluctuation with AG. These findings could be of interest for gymnasts, coaches, ophthalmologists, and/or optometrists in the prevention and control of risk factors associated with glaucoma.

Intraocular pressure fluctuation during resistance exercise

Objective

To evaluate the effect of weightlifting (leg press) on intraocular pressure (IOP).

Design

Prospective cohort study.

Subjects

A total of 24 participants met the inclusion criteria and completed the study procedures. Participants had an average age of 22.7±2.7 years and included nine women. The mean baseline IOP was 13.9 mm Hg (SD=2.4) with an average body mass index of 24.5 (SD= 3.1).

Methods

The maximum load for a single lift was found for each participant. Participants then performed three leg press regimens: one repetition using 95% of maximal load (1RM), six repetitions using 75% of maximal load (6RM) and isometric push against a weight much heavier than maximal load (ISO).

Main outcome measure

IOP was measured pre-exercise, during and immediately following the exercise using an iCare TA01i rebound tonometer. Blood pressure and HR were being monitored continuously during the lift. Optical coherence tomography images were obtained pre and postexercise session.

Results

The average maximum weight lifted by our participants was 331.9 Kg (SD=97.3). Transient increased IOP was observed across the 1RM, 6RM and ISO exercises with an average increase in 26.4 mm Hg (23.7 mm Hg to 28.7 mm Hg) to reach an average max IOP of 40.7 mm Hg (27.8 mm Hg to 54.2 mm Hg), with an absolute maximum of 70 mm Hg in one participant.

Conclusions

There is a transient and dramatic fluctuation in IOP with resistance training. This coupled with regular exposure to resistance training is potentially a significant risk factor for glaucoma. It should be noted that this study has been carried out in a healthy young population, and, thus, the external validity of these results in glaucoma participants requires further investigation.

Effects of Wearing the Elevation Training Mask During Low-intensity Cycling Exercise on Intraocular Pressure

PRCIS

Low-intensity aerobic exercise is recommended to reduce intraocular pressure (IOP) levels. However, this effect depends on several factors. We found that using an elevation training mask (ETM) during low-intensity aerobic exercise causes an IOP rise.

PURPOSE

The aim was to assess the influence of wearing an ETM on IOP during low-intensity endurance training.

METHODS

Sixteen physically active young adults (age=23.9±2.9 y) cycled during 30 minutes at 10% of maximal power production with and without an ETM in 2 different days and randomized order. A rebound tonometer was used to measure IOP at baseline, after a warm-up of 5 minutes, during cycling (6, 12, 18, 24, and 30 min), and recovery (5 and 10 min) by rebound tonometry.

RESULTS

The use of an ETM significantly affects the IOP behaviour during exercise (P<0.001, ηp²=0.66). In the ETM condition, there was an IOP increment during exercise (P<0.001, ηp²=0.28) whereas an IOP-lowering effect was observed in the control condition (P<0.001, ηp²=0.41). Post hoc comparisons showed that there were greater IOP values during exercise in the ETM condition in comparison to the control condition (average IOP difference=3.7±2.2 mm Hg; corrected P<0.01, and the Cohen d's >1.10, in all cases).

CONCLUSION

Low-intensity endurance exercise causes an increment in IOP when it is performed wearing an ETM and a decrease in IOP when the air flow is not restricted (control condition). Therefore, the ETM should be discouraged during low-intensity endurance exercise for individuals who need to reduce IOP levels (eg, glaucoma patients or those at risk). However, the external validity of these results needs to be addressed in future studies with the inclusion of glaucoma patients.

Intraocular Pressure Responses to Four Different Isometric Exercises in Men and Women

SIGNIFICANCE

The performance of resistance exercise has evidenced to induce abrupt intraocular pressure (IOP) changes, which has been linked to the onset and progression of glaucoma. We found that four different isometric resistance exercises lead to an instantaneous and progressive IOP elevation, with these changes being independent of the type of exercise.

PURPOSE

The impact of physical exercise on IOP has demonstrated to be dependent on exercise type and intesity, as well as individuals' characteristics. In this study, we aimed to explore the influence of the load, exercise type, and participant's sex on the IOP behavior during a 2-minute isometric effort.

METHODS

Twenty-eight physically active collegiate students performed 2 minutes of isometric exercise in the military press, biceps curl, leg extension, and calf raise exercises against two different loads (high load and low load). Intraocular pressure was measured by rebound tonometry before, during (semicontinuos assessment [24 measurements]), and after 10 seconds of recovery in each of the eight (four exercises × two loads) conditions.

RESULTS

We found a statistically significant effect of load (P < .001, np = 0.906), with greater IOP values when performing the isometric exercises against heavier loads. There was a positive IOP rise during the execution of isometric exercise in the high-load condition, returning to baseline levels after 10 seconds of passive recovery. The exercise type and participant's sex did not reveal statistically significant differences (P = .33 and P = .56, respectively).

CONCLUSIONS

Our data evidenced an instanteneous and progressive IOP rise during the execution of isometric exercise leading to muscular failure, regardless of the exercise type and participant's sex. After exercise, IOP rapidly retuned to baseline levels (within 10 seconds). The inclusion of glaucoma patients in future studies is guarranteed.

The intraocular pressure response to lower-body and upper-body isometric exercises is affected by the breathing pattern

We assessed the mediating role of the breathing pattern adopted during isometric exercise on the intraocular pressure (IOP) response in the back squat and biceps curl exercises. Twenty physically active young adults performed sets of 1-minute isometric effort against a load corresponding to 80% of the maximum load while adopting three different breathing patterns: (i) Constant breathing: 10 cycles consisting of 3 s of inhalation and 3 s of exhalation, (ii) 10-sec Valsalva: 3 cycles consisting of 10 s holding the breath and 10 s of normal breathing, and (iii) 25-sec Valsalva: 2 cycles consisting of 25 s of the Valsalva maneuver and 5 s of normal breathing. A rebound tonometer was used to semi-continuously assesses IOP during the six sets of 1-minute isometric effort (2 exercises × 3 breathing patterns). We found a progressive IOP rise during isometric effort (P < 0.001, ηp2 = 0.83), with these increases being greater when the breath was held longer (P < 0.001, ηp2 = 0.58; 25-sec Valsalva > 10-sec Valsalva = constant breathing). There was a trend towards higher IOP values for the back squat in comparison to the biceps curl, although these differences did not reach statistical significance for any breathing pattern (corrected P-value ≥ 0.146, d ≤ 0.69). These findings reveal that glaucoma patients or those at risk should avoid activities in which the breath is held, especially when combined with physical exercise modalities that also promote an increment in IOP values (e.g. isometric contractions).

Determinant Factors of Intraocular Pressure Responses to a Maximal Isometric Handgrip Test: Hand Dominance, Handgrip Strength and Sex

PURPOSE

To assess the mediating role of strength levels, hand dominance and participants´ sex on the intraocular pressure (IOP) behaviour during the execution of a maximal isometric handgrip test.

METHODS

One hundred and seventy-six sport science students (102 men and 74 women) performed a maximal isometric handgrip test with the dominant and non-dominant hands. A rebound tonometer was used to measure IOP before effort, during effort, and immediately after performing the handgrip test. Men and women were divided based on their handgrip strength in low- and high-strength groups using a median split analysis.

RESULTS

There was an acute IOP rise during effort, returning to baseline levels immediately after exercise cessation (P < .001, η_p ² = 0.79). A greater increase in IOP during the execution of the handgrip test was observed for the dominant-hand compared to the non-dominant hand (P = .004, d = 0.30) and for men compared to women (P = .001, d = 0.90). The main effect of strength level did not reach statistical significance (P = .266).

CONCLUSIONS

The IOP rise associated with a maximal isometric handgrip effort is affected by the participants´ sex (men > women) and hand dominance (dominant hand > non-dominant hand), but not on strength levels. These findings need to be corroborated in glaucoma patients.

Intraocular pressure increases during dynamic resistance training exercises according to the exercise phase in healthy young adults

PURPOSE

To determine the intraocular pressure (IOP) changes caused by the execution of lower body and upper body resistance training exercises leading to muscular failure depending on the exercise phase (concentric vs. eccentric). We also assessed the influence of the exercise type (back squat vs. biceps curl) and level of effort on the IOP response.

METHODS

Nineteen physically active young adults performed four sets (2 exercise type × 2 exercise phase) of 10 repetitions leading to muscular failure while adopting a normal breathing pattern. IOP was measured by rebound tonometry at baseline, after each of the ten repetitions, and after 1 min of recovery.

RESULTS

There was a main effect of the exercise phase (p < 0.001, η² = 0.56), observing greater IOP values in the eccentric condition of the back squat and concentric condition of the biceps curl. Also, greater IOP values were obtained for the back squat in comparison with the biceps curl (p < 0.001, η² = 0.61), and IOP progressively increases with the level of accumulated effort (p < 0.001, η² = 0.88; Pearson r = 0.97-0.98).

CONCLUSIONS

IOP fluctuates during the different phases of the repetition in dynamic resistance training exercises, being greater IOP values observed during the more physically demanding phases of the exercise (eccentric phase of the back squat and concentric phase of the biceps curl). A heightened IOP response is positively associated with muscle size (back squat > biceps curl) and with the level of effort (number of accumulated repetitions). Based on these findings, highly demanding dynamic resistance training should be avoided when maintaining stable IOP levels is desirable.

Effects of Blood Flow Restriction at Different Intensities on IOP and Ocular Perfusion Pressure

SIGNIFICANCE

The use of blood flow restriction allows obtaining beneficial physical adaptions when combined with low-intensity exercise or even when used alone. We found that using blood flow restriction may be a potential strategy to avoid IOP and ocular perfusion pressure fluctuations provoked by strength and endurance training.

PURPOSE

The purpose of this study was to assess the influence of bilateral blood flow restriction in the upper and lower body at two different intensities on IOP and ocular perfusion pressure, as well as the possible sex differences.

METHODS

Twenty-eight physically active university students (14 men and 14 women) took part in the study, and blood flow restriction was bilaterally applied with two pressures in the legs and arms. There were five experimental conditions (control, legs-high, legs-low, arms-high, and arms-low). IOP was measured by rebound tonometry before, during (every 4 seconds), and immediately after blood flow restriction. Ocular perfusion pressure was measured before and after blood flow restriction.

RESULTS

We found that only the arms-high condition promoted a statistically significant IOP rise when compared with the rest of the experimental conditions (all Bayes factors10, >100; effect sizes, 1.18, 1.06, 1.35, and 1.73 for the control, arms-low, legs-high, and legs-low conditions, respectively). For ocular perfusion pressure, there was strong evidence for the null hypothesis regarding the type of blood flow restriction (Bayes factor10, 0.012); however, men showed an ocular perfusion pressure reduction after blood flow restriction in the arms-high condition (Bayes factor10, 203.24; effect size, 1.41).

CONCLUSIONS

This study presents preliminary evidence regarding the safety of blood flow restriction in terms of ocular health. Blood flow restriction may be considered as an alternative training strategy to reduce abrupt fluctuations in IOP and ocular perfusion pressure because its use permits a considerable reduction of exercise intensity.

Intraocular Pressure as an Indicator of the Level of Induced Anxiety in Basketball

SIGNIFICANCE

Our data demonstrate that intraocular pressure (IOP) is sensitive to anxiety manipulation in sport scenarios, specifically in a basketball free throw task. The present outcomes may be of special relevance because of its practical advantages for the objective control of athletes' anxiety levels.

PURPOSE

Athletes experience high levels of anxiety during sport competition, and IOP has demonstrated to reflect autonomous nervous system changes during mentally demanding situations. We tested whether different levels of induced anxiety during basketball free throw shooting alter IOP.

METHODS

We followed a repeated-measures design to test the effects of anxiety-induced manipulation during basketball free throw shooting on IOP, shooting performance, and perceived anxiety. Eighteen amateur basketball players performed three experimental sessions consisting of 100 free throws each. However, we gave three different instructions to participants regarding the score assigned to each free throw, allowing us to manipulate the level of induced anxiety (low, medium, and high).

RESULTS

Confirming a successful anxiety manipulation, basketball players reported more perceived anxiety with higher levels of induced anxiety (P < .001, η = 0.37). Our data show that higher levels of induced anxiety provoke an acute IOP rise (P < .001, η = 0.44), with the low-, medium-, and high-anxiety-induced conditions promoting an average IOP rise of 0.21, 1.63, and 18.46%, respectively. Also, there was a linear IOP rise over time in the high-anxiety-induced condition (r = 0.82). Nevertheless, we found no effect of anxiety-induced manipulation on basketball free throw performance (P = .93).

CONCLUSIONS

Intraocular pressure is sensitive to anxiety-induced manipulation during basketball free throw shooting, showing an increase in parallel with accumulated anxiety. Based on these findings, IOP may be considered a promising tool for the assessment of the level of anxiety in certain sport situations. Future studies are required to explore the generalizability of these results in other scenarios with different physical and mental demands.

Impact of resistance training sets performed until muscular failure with different loads on intraocular pressure and ocular perfusion pressure

PURPOSE

The aim of this article is to investigate the acute effects of bench press sets leading to muscular failure with different loads on intraocular pressure and ocular perfusion pressure.

STUDY DESIGN

A randomized experimental study.

METHODS

Seventeen physically active young men performed four resistance training sets of bench press to muscular failure against different relative loads (65% one-repetition maximum vs 75% one-repetition maximum vs 85% one-repetition maximum vs 95% one-repetition maximum). Intraocular pressure was measured before and immediately after the execution of each of the four sets, and ocular perfusion pressure was also assessed before and after physical effort.

RESULTS

We found that intraocular pressure increased after reaching muscular failure (p < 0.001, ƞ²= 0.52), being also dependent on the interaction load × point of measure (p < 0.001, ƞ²= 0.33). Our data demonstrated that higher intraocular pressure increases were found when participants performed the bench press exercise against heavier loads, showing statistical significance for the 75% one-repetition maximum (p = 0.020, d = -0.63, mean change = 0.9 mmHg), 85% one-repetition maximum (p = 0.035, d = -0.56, mean change = 1.4 mmHg), and 95% one-repetition maximum (p < 0.001, d = -1.36, mean change = 2.9 mmHg) relative loads. For its part, ocular perfusion pressure showed a reduction after exercise (p = 0.009, ƞ²= 0.35), being these changes independent on the load used.

CONCLUSION

Bench press exercise leading to muscular failure provokes an acute intraocular pressure rise, with greater changes when heavier loads are used. Ocular perfusion pressure exhibited an acute reduction after exercise; however, its clinical relevance seems to be insignificant (lower to 4%). We argue that the use of heavy loads, when training to muscular failure, should be discouraged in order to avoid acute intraocular pressure fluctuations. Future studies should corroborate the generalizability of these findings in glaucoma patients.

Influence of holding weights of different magnitudes on intraocular pressure and anterior eye biometrics

PURPOSE

This study is aimed at determining the impact of holding weight corresponding to the 10% and 20% of participants' body weight during 5-min on intraocular pressure (IOP) and anterior eye biometrics.

METHODS

Eighteen healthy young adults grabbed two jugs with comfort-grip handles, which were filled with water in order to achieve the desirable load (10% and 20% of participants' body weight). A rebound tonometer and Oculus Pentacam were used to assess IOP and anterior segment biometrics, respectively, at baseline, after 0.5, 2, 3.5, and 5 min of holding weights, as well as after 0.5 and 2 min of recovery in each experimental condition (control, 10%, and 20%).

RESULTS

There was a significant effect of the load used on IOP (p = 0.016, ƞ_p² = 0.215) and anterior chamber angle (p = 0.018, ƞ_p² = 0.211), with the load corresponding to 20% of participants' body weight promoting a significant IOP rise (corrected p value = 0.035, d = 0.67), and anterior chamber angle reduction (corrected p value = 0.029, d = 0.69) in comparison with the control condition. No effects of holding weight were observed for anterior chamber depth and central corneal thickness (p > 0.348).

CONCLUSIONS

Our data evidence that holding weight during 5 min increases IOP and narrows the anterior chamber angle, being these effects significant when using a load corresponding to 20% of body weight. Based on the current outcomes, lifting or carrying heavy loads may be discouraged for glaucoma patients or individuals at high risk for glaucoma onset, although future studies should explore the clinical relevance of our findings.

Influence of the breathing pattern during resistance training on intraocular pressure

This study aimed to assess the effect of the breathing pattern during resistance training on intraocular pressure (IOP). Twenty physically active collegiate students (7 women and 13 men) performed sets of 10 repetitions against the 10-RM (repetition maximum) load during the back-squat and biceps-curl exercises following 3 different breathing patterns: (I) Valsalva: holding the breath during the entire repetition; (II) normal breathing: holding the breath and exhaling during the first and second phases of the repetition, respectively; and (III) modified breathing: inhaling and holding the breath during the first and second phases of the repetition, respectively. Rebound tonometry was used to measure IOP before exercise, after each of the 10 repetitions, and after 1 min of recovery. The breathing pattern significantly affected the changes in IOP values (p < 0.001, [Formula: see text] = 0.509) with the normal breathing pattern providing lower increases in IOP values compared to the Valsalva (p < 0.001, d = 1.47) and modified breathing (p < 0.001, d = 0.96). Higher IOP values were observed for the back-squat compared to the biceps-curl exercise (p = 0.003, [Formula: see text] = 0.384). A normal breathing pattern should be recommended to avoid abrupt increments in IOP during resistance training. These findings may be especially important for individuals at high risk for glaucoma onset or progression due to the necessity of maintaining stable IOP levels to avoid the progression of this disease. In future studies, the inclusion of glaucoma patients would allow to assess the generalizability of these findings.

Investigating the Immediate and Cumulative Effects of Isometric Squat Exercise for Different Weight Loads on Intraocular Pressure: A Pilot Study

BACKGROUND

The execution of resistance exercise against heavy loads promotes an acute intraocular pressure (IOP) rise, which has detrimental effects on ocular health. However, the effect of load on the IOP behavior during exercise remains unknown due to technical limitations.

HYPOTHESES

IOP monitoring during isometric squat exercise permits assessment of IOP behavior during physical effort. Second, greater loads will induce a higher IOP rise.

STUDY DESIGN

Randomized cross-sectional study.

LEVEL OF EVIDENCE

Level 2.

METHODS

Twenty-six young adults (13 women, 13 men) performed an isometric squat exercise against 3 loads relative to their maximum capacity (low, medium, and high). IOP was measured before, during (1 measurement every 6 seconds), and after exercise (10 seconds of recovery).

RESULTS

There was a progressive IOP rise during exercise, which was dependent on the load applied (Bayes factor₁₀ >100). Higher IOP values were found in the high load condition in comparison with the medium (mean IOP difference = 1.5 mm Hg) and low (mean IOP difference = 3.1 mm Hg) conditions, as well as when the medium load was compared with the low load condition (mean IOP difference = 1.6 mm Hg). Men reached higher IOP values in comparison with women during the last measurements in the high load condition. Ten seconds of recovery were enough to obtain IOP values similar to baseline levels.

CONCLUSION

Isometric squat exercise induces an immediate and cumulative IOP elevation, which is positively associated with the load applied. These IOP increments return to baseline values after 10 seconds of recovery, and men demonstrate a more accentuated IOP rise in comparison with women when high levels of effort are accumulated.

CLINICAL RELEVANCE

These findings may help in better management of different ocular conditions and highlight the importance of an individualized exercise prescription in clinical populations.

Effect of a maximal treadmill test on intraocular pressure and ocular perfusion pressure: The mediating role of fitness level

Objectives:

We compared the impact of a maximal treadmill test on intraocular pressure and ocular perfusion pressure between trained and untrained individuals.

Methods:

Based on the maximal aerobic capacity (relative VO2 max), 31 military helicopter pilots were divided into groups of trained (n = 16; VO2 max = 57.06 ± 1.66) and untrained (n = 15; VO2 max = 43.42 ± 1.19) individuals. Intraocular pressure and blood pressure were collected before effort, just after volitional exhaustion and after 5 and 15 min of recovery.

Results:

The maximal treadmill test induced significant changes on intraocular pressure (p < 0.001, η2 = 0.52) and ocular perfusion pressure (p < 0.001, η2 = 0.60). Intraocular pressure and ocular perfusion pressure increased just after volitional exhaustion (effect size = 0.88 and 1.59, respectively), and these values returned to baseline levels after 5 (effect size = 0.87 and 1.26, respectively) and 15 (effect size = 1.23 and 1.91, respectively) min of recovery. The untrained group exhibited higher intraocular pressure and ocular perfusion pressure values in comparison with the trained group just after volitional exhaustion (effect size = 1.43 and 0.11 for intraocular pressure and effect size = 2.81 and 0.96 for ocular perfusion pressure). Five minutes of recovery was insufficient to reach baseline intraocular pressure and ocular perfusion pressure values only for the untrained group (effect size = 0.91 and 0.72, respectively).

Conclusion:

Our findings reveal that fitness level modulates the intraocular pressure and ocular perfusion pressure responses to a maximal treadmill test, being high fitness levels desirable in order to attenuate the impact of maximal efforts on these indices. These outcomes may be of clinical relevance for the management of glaucoma patients or those at risk, although future studies are needed to test these results in a clinical population.

Intraocular pressure increases after complex simulated surgical procedures in residents: an experimental study

BACKGROUND

Surgeons' overload is one of the main causes of medical errors that might compromise patient safety. Due to the drawbacks of current options to monitor surgeons' load, new, sensitive, and objective indices of task (over)load need to be considered and tested. In non-health-care scenarios, intraocular pressure (IOP) has been proved to be an unbiased physiological index, sensitive to task complexity (one of the main variables related to overload), and time on task. In the present study, we assessed the effects of demanding and complex simulated surgical procedures on surgical and medical residents' IOP.

METHODS

Thirty-four surgical and medical residents and healthcare professionals took part in this study (the experimental group, N = 17, and the control group, N = 17, were matched for sex and age). The experimental group performed two simulated bronchoscopy procedures that differ in their levels of complexity. The control group mimicked the same hand-eye movements and posture of the experimental group to help control for the potential effects of time on task and re-measurement on IOP. We measured IOP before and after each procedure, surgical performance during procedures, and perceived task complexity.

RESULTS

IOP increased as consequence of performing the most complex procedure only in the experimental group. Consistently, residents performed worse and reported higher perceived task complexity for the more complex procedure.

CONCLUSIONS

Our data show, for the first time, that IOP is sensitive to residents' task load, and it could be used as a new index to easily and rapidly assess task (over)load in healthcare scenarios. An arousal-based explanation is given to describe IOP variations due to task complexity.

Effect of the level of effort during resistance training on intraocular pressure

BACKGROUND

We aimed to evaluate the influence of the level of effort during four basic resistance exercises leading to muscular failure on intraocular pressure (IOP) and ocular perfusion (OPP), as well as the role of exercise type and sex.

METHODS

Twenty-five young adults (12 women) performed 10 repetitions against their 10-RM (repetition maximum) load in the squat, military press, biceps curl and calf raise exercises. IOP was measured before, during and after exercise, whereas OPP was indirectly assessed before and after each exercise.

RESULTS

There was a progressive IOP rise during exercise (p < 0.001, η² = 0.531), which was dependent on exercise type (p = 0.020, η² = 0.125). The squat exercise induced higher IOP increments in comparison to the other exercises (corrected p-values < 0.001), and higher IOP values were found for the military press and biceps curl than for the calf raise exercise (corrected p-values = 0.012 and 0.002). OPP exhibited a significant reduction when leading to muscular failure (p = 0.001, η² = 0.364), being statistically significant for the squat and military press exercises (corrected p-values = 0.037 and 0.047). No effect of sex was found for IOP and OPP (p > 0.05).

CONCLUSIONS

A single set of resistance training leading to muscular failure causes an instantaneous and progressive IOP rise in healthy young individuals. These IOP rises depend on exercise type (squat > military press = biceps curl > calf raise), but not on participant´s sex. OPP diminished as a consequence of performing resistance training exercise, being statistically significant for the squat and military press exercises. Future studies should include glaucoma patients aiming to corroborate the generalizability of our findings.

Baseline Intraocular Pressure Is Associated With Subjective Sensitivity to Physical Exertion in Young Males

PURPOSE

The purposes of this study were to (a) investigate the effect of physical effort (cycling for 60 min at 60 ± 5% of individually computed reserve heart-rate capacity), combined with 2 different levels of cognitive demand (2-back, oddball), on intraocular pressure (IOP) and subjective judgments of perceived exertion (ratings of perceived exertion [RPE]), affect (Affective Valence subscale of the Self-Assessment Manikin [SAM]), and mental workload (National Aeronautics and Space Administration Task Load Index [NASA-TLX]); and (b) ascertain whether baseline IOP, measured before exercise, is associated with individual differences in subjective assessments of effort and affective response during exercise.

METHOD

Seventeen participants (M_age = 23.28 ± 2.37 years) performed 2 physical/cognitive dual tasks, matched in physical demand but with different mental requirements (2-back, oddball). We assessed IOP before exercise, after 2 min of active recovery, and after 15 min of passive recovery, and we also collected RPE and SAM measures during the sessions (28 measurement points). We used NASA-TLX and cognitive performance as checks of the mental manipulation.

RESULTS

(a) Intraocular pressure increased after concomitant physical/mental effort, with the effect reaching statistical significance after the 2-back task (p = .002, d = 0.35) but not after the oddball condition (p = .092, d = 0.29). (b) Baseline IOP was associated with subjective sensitivity to effort and showed statistical significance for the oddball condition (p = .03, ƞ_p² = .622) but not for the 2-back task (F < 1).

CONCLUSIONS

Results suggest a relationship between IOP and physical/cognitive effort, which could have implications for the management of glaucoma. Additionally, a rapid measure of IOP could be used as a marker of individual effort sensitivity in applied settings.

Fitness Level Modulates Intraocular Pressure Responses to Strength Exercises

Purpose/Aim: The execution of strength exercises has demonstrated to increase the intraocular pressure (IOP) levels, and it may have a negative impact on the ocular health. We aimed to explore the influence of fitness level on the acute IOP response to strength exercises performed under different loading conditions, as well as to test whether the IOP responses differ between the bench press and jump squat when performed against the same relative loads.

MATERIALS AND METHODS

Forty military personnel males were divided in two subgroups (20 high-fit and 20 low-fit) based on their relative to body mass one-repetition maximum (1-RM). Participants performed an incremental loading test in the bench press and jump squat exercises, and IOP was assessed before and after each repetition by rebound tonometry.

RESULTS

IOP increased immediately after executing both exercises (p < 0.01 in both cases), being the magnitude of the IOP increment positively and linearly associated with the increment of the load in both groups (i.e., high-fit and low-fit) and in both exercises (R² range: 0.81-1.00). Higher fitness level attenuated the IOP rise produced by both exercises (p < 0.01 in both cases). The bench press induced higher IOP increments than the jump squat for both groups at relative loads of ~50%1-RM and ~60%1-RM (p < 0.01 in all cases).

CONCLUSIONS

These data indicate that IOP increases as a consequence of performing strength exercises, being the increment accentuated with the increase of the load and in the bench press compared to the jump squat exercise. Of special importance would be that the IOP responses were significantly reduced in high-fit individuals. These findings should be addressed in glaucoma patients.

Muscular Strength Is Associated with Higher Intraocular Pressure in Physically Active Males

SIGNIFICANCE

The positive association between intraocular pressure (IOP) and relative maximum force may have relevance for exercise recommendations when IOP is a concern.

PURPOSE

The relationship between exercise and IOP has been approached in several studies. However, the influence of muscle function on IOP remains underexplored. This study aimed to determine the relationship between the maximal mechanical capabilities of muscles to generate force, velocity, and power with IOP.

METHODS

Sixty-five physically active males participated in this cross-sectional study. Baseline IOP measures were obtained by rebound tonometry, and participants performed an incremental loading test in the ballistic bench press.

RESULTS

Baseline IOP showed a strong positive correlation with relative maximum force (r65 = 0.85, P < .001) relative maximum power (r65 = 0.85, P < .001), and relative one-repetition maximum (r65 = 0.91, P < .001). Also, a moderate positive association was obtained between baseline IOP and maximum force (r65 = 0.74, P < .001), maximum power (r65 = 0.72, P < .001), and maximum dynamic strength (r65 = 0.80, P < .001). No significant correlations between IOP and maximal velocity were obtained (all P > .05).

CONCLUSIONS

There is a positive association between greater upper-body power and strength with higher baseline IOP, which might have important implications in the management of ocular health and especially in individuals constantly involved in resistance training programs (e.g., military personnel, weightlifters). The possible protective effect of high fitness level on the acute IOP response to strength exercise needs to be addressed in future studies.