Relationship between post-exercise heart rate variability and skinfold thickness

Body fat and muscle in relation to heart rate variability in young-to-middle age men: a cross sectional study

BACKGROUND

While obesity is recognisably associated with changes in heart rate variability (HRV), the association between skeletal muscle mass and HRV is less clear.

AIMS

In this cross sectional study, we analysed the association of body fat (four parameters) and muscle mass (five parameters) with indicators of HRV activity.

SUBJECTS AND METHODS

Assessment of body composition and HRV was performed in n = 180 young-to-middle age healthy men exposed to high occupational physical activity, using the multi-frequency bioelectrical impedance device and the PPG-StressFlow® HRV photoplethysmography device, respectively.

RESULTS

Mean values of parameters of fat tissue were above normal/reference values. Muscle tissue indicators were higher or within the reference ranges. Fat tissue parameters were significantly higher in participants with lower parasympathetic nervous system (PNS) indicators. Weight-adjusted skeletal muscle index (wSMI) was significantly lower in men with reduced PNS parameters. Fat tissue parameters were negatively correlated with PNS parameters, while wSMI was positively correlated with PNS parameters.

CONCLUSIONS

Participants with higher fat mass and lower muscle mass had poorer parasympathetic activity. Since mean values of HRV parameters indicated mild parasympathetic dominance, we conclude that physical activity and consequently good muscle mass potentially compensated for the negative interaction between fat tissue and HRV.

Body fat content correlates with maximum aerobic capacity in healthy sedentary Indian males

Background

Obesity is a multifactorial public health problem with varying effects on physical fitness determined by maximum aerobic capacity or VO2max. The relationship between body fat content and VO2max has shown varying results. The present study was planned as an experimental study to evaluate the relationship between body fat content and maximum aerobic capacity.

Methods

104 healthy Indian males [Age: 21 (4.87)years; Height: 171.4 (6.14)cm; Weight: 64.1 (8.57)kg] were evaluated for body fat content using body mass index (BMI), bioimpedance, skinfold thickness (SFT), body girth (BG) measurements, waist circumference (WC), and waist-hip ratio (WHR). Maximum aerobic capacity or VO2max for all subjects was determined indirectly from maximum heart rate achieved using an incremental treadmill protocol using Astrand and Astrand nomogram.

Results

VO2max, when expressed in L/min, showed a statistically significant positive correlation with body fat irrespective of the method of estimation. VO2max, when expressed in ml/kg/min, showed negative correlation with five of the seven clinical parameters of fat estimation. Of these, a statistically significant negative correlation was seen with SFT.

Conclusion

VO2max (L/min) shows a significant positive correlation with all methods of body fat estimation. VO2max (ml/kg/min) shows a significant negative correlation with skinfold thickness. Monitoring of body fat content using skinfold thickness could be studied further for its use in the early identification of young, healthy adult Indian males with low aerobic fitness.

Cardiac autonomic disturbance following resistance and sprint-interval exercises in non-obese and obese young men

This study examined the alterations of heart rate variability (HRV) following iso-duration resistance (RES) and sprint-interval (SIE) exercises by comparing with that of non-exercise control (CON) in 14 non-obese (NOB) and 15 obese (OB) young men. Time and frequency domain measures as well as non-linear metrics of HRV were assessed before and immediately after exercise, and during every 20 min until 120 min post exercise. The variables during the first 4 hrs of actual sleep time at night, and the period of 12-14 hrs post exercise were also measured. All trials were scheduled at 20:00. It was found that RES and SIE attenuated the HRV in both NOB and OB (P <0.05), and the attenuated HRV restored progressively during subsequent recovery. Although the changes in HRV indices among various time points during the recovery period and its interaction across RES, SIE and CON were not different between NOB and OB, the restoration of the declined HRV indices to corresponding CON level in the two exercise trials in OB appeared to be sluggish in relative to NOB. Notwithstanding, post-exercise HRV that recorded during actual sleep at night and during 12-14 hrs apart from exercise were unvaried among the three trials in both groups (P>0.05). These findings suggest that obesity is likely to be a factor hindering the removal of exercise-induced cardiac autonomic disturbance in young men. Nonetheless, the declined HRV following both the RES and SIE protocols were well restored after a resting period of ~10 hrs regardless of obesity. The study was registered at ISRCTN as DOI:10.1186/ISRCTN88544091.

Active women demonstrate acute autonomic and hemodynamic shifts following exercise in heat and humidity: A pilot study

The purpose of this study was to assess autonomic and hemodynamic recovery in women who performed moderate-intensity exercise in heat. Seven women (31.7 ± 7.6 years, 67.5 ± 4.4 kg, 25.7 ± 5.6% Fat, 43.9 ± 5.1 mL/kg/min) completed two identical bouts of graded treadmill walking (~60% VO₂peak). One bout was hot (37.5 ± 1.4°C, 46.5 ± 4.6% relative humidity (RH)), and the other was moderate (20.7 ± 1.1°C, 29.9 ± 4.1% RH). For 24 h before and one h after each bout, participants had heart rate variability monitored. After each exercise bout HR and BP were measured during 30 min of supine recovery and 10 min of orthostatic challenge. HF power and RMSSD were lower and LF power and LF:HF ratio greater following exercise in the heat and remained different from the moderate condition for 30 min (p < 0.05). During supine recovery, heat exposure led to higher HR (p = 0.002) and lower DBP (p = 0.016). SBP (p = 0.037) and DBP (p = 0.008) were both lower after 10 min of supine recovery following hot exercise than after moderate temperature. Average response did not reveal orthostatic hypotension despite heat causing a higher HR (p = 0.011) and lower SBP (p = 0.026) after 10 min of orthostatic exposure. Trained women exhibit an autonomic shift toward sympathetic dominance for at least 30 min after exercise in heat. Women who exercise in heat should be wary of an exacerbated HR response after exercise and low recovery blood pressures.

AGING, HEART RATE VARIABILITY AND METABOLIC IMPACT OF OBESITY

The relationship between aging and changes in heart rate variability (HRV) could depend on the metabolic profile of obese people, i.e. metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO). We aimed to determine the age at which obesity related autonomic dysfunction becomes significant and whether it decreases differently according to metabolic profile. We analyzed HRV in 99 adults using Wildman's criteria for metabolic profile and 5-minute HRV for autonomic nervous system. In MHO, high frequency (HF) decreased in the 4^th decade of life. In MUO, standard deviation of R-R intervals (SDNN), root mean square of successive differences of all R-R intervals (RMSSD), number of adjacent intervals differing by more than 50 ms expressed as percentage of all intervals in the collecting period (pNN50), HF, low frequency (LF), LF/HF (LF divided by HF) and total power (TP) decreased in the 4^th decade of life (partial shared variance 28%-36%). In conclusion, an age dependent decrease of HRV occurs in MUO between the third and fifth decade of life. In MHO, HF significantly decreases around the age of 40 years. Cardiometabolic profile influences metabolic aging, altering the autonomic nervous system.

Comparison of different volumes of high intensity interval training on cardiac autonomic function in sedentary young women

Purpose The present study was conducted to compare the effects of low volume of high intensity interval training (LVHIIT) and high volume of high intensity interval training (HVHIIT) on heart rate variability (HRV) as a primary outcome measure, and on maximum oxygen consumption (VO2max), body composition, and lower limb muscle strength as secondary outcome measures, in sedentary young women. Methods Thirty-six participants were recruited in this study. The LVHIIT group (n = 17) performed one 4-min bout of treadmill running at 85%-95% maximum heart rate (HRmax), followed by 3 min of recovery by running at 70% HRmax, three times per week for 6 weeks. The HVHIIT group (n = 15) performed four times 4-min bouts of treadmill running at 85%-95% HRmax, interspersed with 3-min of recovery by running at 70% HRmax, 3 times per week for 6 weeks. All criterion measures were measured before and after training in both the groups. Results Due to attrition of four cases, data of 32 participants was used for analysis. A significant increase in high frequency (HF) power (p < 0.001) and decrease in the ratio of low frequency to high frequency power (LF/HF) ratio (p < 0.001) in HRV parameters, was observed post-HVHIIT, whereas, these variables did not change significantly (HF: p = 0.92, LF/HF ratio: p = 0.52) in LVHIIT group. Nevertheless, both the interventions proved equally effective in improving aerobic capacity (VO2max), body composition, and muscle strength. Conclusion The study results suggest that both LVHIIT and HVHIIT are equally effective in improving VO2max, body composition, and muscle strength, in sedentary young women. However, HVHIIT induces parasympathetic dominance as well, as measured by HRV.

Influence of a CYP1A2 polymorphism on post-exercise heart rate variability in response to caffeine intake: a double-blind, placebo-controlled trial

BACKGROUND

Proposed differences in caffeine metabolism due to the CYP1A2*1F polymorphism have been linked to variations in cardiovascular disease risk.

AIMS

We examined the influence of a CYP1A2*1F polymorphism on post-exercise heart rate variability (HRV) in response to caffeine intake.

METHODS

Volunteers were identified as A/A homozygotes (A/A; 4 females and 7 males; age: 25.3 ± 4.1 years; BMI: 25.9 ± 4.4 kg/m²) or C allele carriers (C allele; 3 females and 6 males; age: 25.5 ± 2.8 years; BMI: 26.6 ± 5.0 kg/m²) for participation in a repeated measures, counterbalanced, double-blind, placebo-controlled trial. Participants chewed three pieces of gum containing either caffeine (CAF) (100 mg/piece) or placebo for 5 min. Thereafter, participants cycled for 15 min at 75 % of their peak oxygen consumption. Eight HRV indices computed during 5 min at baseline (BASE), 0-5 min after exercise (POST1), and 5-10 min after exercise (POST2) were used for analysis.

RESULTS

No significant group differences were detected in HRV indices at BASE, POST1, or POST2 during both trials (p > 0.05). Rate of recovery (POST2-POST1) for the square root of the mean of squared differences between successive RR intervals (RMSSD) was significantly different between A/A (6.0 ± 2.5 ms) and C allele (3.6 ± 2.5 ms) groups during the CAF trial (p = 0.048).

CONCLUSIONS

Rate of RMSSD recovery was the only variable influenced by the CYP1A2*IF polymorphism during post-exercise in response to caffeine intake. Thus, the CYP1A2*1F polymorphism did not overtly influence the effects of caffeine intake on post-exercise HRV.

Association between anthropometric measures of regional fat mass and heart rate variability in obese women

AIM

Impaired autonomic function could be the mechanism for the development of cardiometabolic diseases in obesity. Hence, simple anthropometric measures of overall and central obesity could be screening markers for autonomic imbalance. We analysed the relationship between heart rate variability (HRV) parameters and obesity indicators.

METHODS

Sixty-three obese women underwent blood pressure, lipids and anthropometric measurements, body composition assessment, HOMA (homeostasis model assessment) index calculation and short-term HRV analysis.

RESULTS

The correlation between obesity indicators and HRV parameters was influenced by age. In the multiple regression model, sagittal abdominal diameter (SAD) was a significant negative predictor of lnLF/HF (logarithmically transformed ratio of low to high frequencies) and lnLFnorm, and positive predictor of HFnorm (normalized high frequencies); the significant relationship remained even after adjustment for age, HOMA, blood pressure, lipid profile, menopause, body mass index (BMI) and body fat percentage (FAT). Anterior forearm skinfold showed inverse association with HRV. Correlation between waist circumference and waist-to-height ratio (WHtR) with lnLF/HF, as well as between anterior thigh skinfold with lnLF/HF, LFnorm (normalised low frequencies) and HFnorm was lost after further adjustments.

CONCLUSION

Among all anthropometric measures, SAD and anterior forearm skinfold thickness showed the highest predictive ability for HRV. Markers of lower sympathetic and higher cardiac parasympathetic activity corresponded with indicator of central obesity, while indicators of peripheral obesity showed completely opposite relationship with markers of cardiac autonomic activity.

Postexercise heart rate variability following treadmill and cycle exercise: a comparison study

The purpose of this study was to compare postexercise heart rate variability (HRV) immediately following acute bouts of treadmill (T) and cycle (C) exercise at 65% of mode-specific maximal oxygen consumption reserve (65% VO₂ R). Fourteen apparently healthy men participated in this study. On two separate and randomized days, each participant performed 30 min of exercise at 65% VO₂ R on T and C. Supine HRV was evaluated as normalized and log-transformed (ln) high-frequency (HF) and low-frequency (LF) spectral power, as well as the LF:HF ratio in 5-min segments immediately before (PRE) and at 10-15 min (POST1) and 25-30 min (POST2) following each exercise bout. There were no significant differences in the HRV values at PRE between the modalities. Following each exercise bout, lnHF was significantly lower at POST2 following C compared to T. In addition, lnLF and LF:HF were significantly higher at POST1 and POST2 following C compared to T. All HRV metrics returned towards baseline 30 min following T but remained significantly different than PRE values after C. These results suggest that following exercise at 65% of mode-specific VO₂ R, C is associated with a greater delay of postexercise HRV recovery than T in apparently healthy men.