Peak oxygen uptake. Myth and truth about an internationally accepted reference value

Verification of Maximal Oxygen Uptake in Active Military Personnel During Treadmill Running

ABSTRACT

Figueiredo, PS, Looney, DP, Pryor, JL, Doughty, EM, McClung, HL, Vangala, SV, Santee, WR, Beidleman, BA, and Potter, AW. Verification of maximal oxygen uptake in active military personnel during treadmill running. J Strength Cond Res 36(4): 1053-1058, 2022-It is unclear whether verification tests are required to confirm "true" maximal oxygen uptake (V̇o2max) in modern warfighter populations. Our study investigated the prevalence of V̇o2max attainment in U.S. Army soldiers performing a traditional incremental running test. In addition, we examined the utility of supramaximal verification testing as well as repeated trials for familiarization for accurate V̇o2max assessment. Sixteen U.S. Army soldiers (1 woman, 15 men; age, 21 ± 2 years; height, 1.73 ± 0.06 m; body mass, 71.6 ± 10.1 kg) completed 2 laboratory visits, each with an incremental running test (modified Astrand protocol) and a verification test (110% maximal incremental test speed) on a motorized treadmill. We evaluated V̇o2max attainment during incremental testing by testing for the definitive V̇O2 plateau using a linear least-squares regression approach. Peak oxygen uptake (V̇o2peak) was considered statistically equivalent between tests if the 90% confidence interval around the mean difference was within ±2.1 ml·kg-1·min-1. Oxygen uptake plateaus were identified in 14 of 16 volunteers for visit 1 (87.5%) and all 16 volunteers for visit 2 (100%). Peak oxygen uptake was not statistically equivalent, apparent from the mean difference in V̇o2peak measures between the incremental test and verification test on visit 1 (2.3 ml·kg-1·min-1, [1.3-3.2]) or visit 2 (1.1 ml·kg-1·min-1 [0.2-2.1]). Interestingly, V̇o2peak was equivalent, apparent from the mean difference in V̇o2peak measures between visits for the incremental tests (0.0 ml·kg-1·min-1 [-0.8 to 0.9]) but not the verification tests (-1.2 ml·kg-1·min-1 [-2.2 to -0.2]). Modern U.S. Army soldiers can attain V̇o2max by performing a modified Astrand treadmill running test. Additional familiarization and verification tests for confirming V̇o2max in healthy active military personnel may be unnecessary.

Effect of Carbohydrate Content in a Pre-event Meal on Endurance Performance-Determining Factors: A Randomized Controlled Crossover-Trial

The current study aimed to investigate the effect of the relative CHO content in a pre-event meal on time to exhaustion (TTE), peak oxygen uptake (V∙O2peak), the 2nd lactate threshold (LT2), onset of blood lactate accumulation (OBLA), and work economy (WE) and to compare responses between well-trained and recreationally trained individuals. Eleven well-trained and 10 recreationally trained men performed three trials in a randomized cross-over design, in which they performed exercise tests (1) after a high-CHO pre-event meal (3 g · kg⁻¹), (2) a low-CHO pre-event meal (0.5 g · kg⁻¹), or (3) in a fasted-state. The test protocol consisted of five submaximal 5-min constant-velocity bouts of increasing intensity and a graded exercise test (GXT) to measure TTE. A repeated measure ANOVA with a between-subjects factor (well-trained vs. recreational) was performed. A main effect of pre-event meal was found (p = 0.001), with TTE being 8.0% longer following the high-CHO meal compared to the fasted state (p = 0.009) and 7.2% longer compared to the low-CHO meal (p = 0.010). No significant effect of pre-event meal on V∙O2peak, LT2, OBLA, or WE (p ≥ 0.087) was found and no significant interaction effect between training status and pre-event CHO intake was found for TTE or any of the performance-determining variables (p ≥ 0.257). In conclusion, high-CHO content in the pre-event meal led to a longer TTE compared to a meal with a low-CHO content or exercising in a fasted state, both in well-trained and recreationally trained participants. However, the underlying physiological reason for the increased TTE is unclear, as no effect of pre-event meal on the main physiological performance-determining variables was found. Thus, pre-event CHO intake should be standardized when the goal is to assess endurance performance but seems to be of less importance when assessing the main performance-determining variables.

Effects of aerobic and anaerobic exercise on glucose tolerance in patients with coronary heart disease and type 2 diabetes mellitus

In patients with coronary heart disease (CHD) and type 2 diabetes mellitus (T2DM), physical activity is strongly advised as nonpharmacological therapy. In general, a moderate aerobic exercise intensity is recommended. It was also proposed, however, that greater intensities tend to yield even greater benefits in HbA1c. Hence, the most appropriate exercise intensity seems not to be established yet. We compared the effect of moderate (aerobic) and vigorous (anaerobic) activity on postprandial plasma glucose.

Methods

In 10 consecutive patients (63 ± 12 years, BMI 28.3 ± 2.6 kg/m², fasting plasma glucose 6.1 ± 1.2 mmol/l), 2-hour plasma glucose was ≥11.1 mmol/l in the oral glucose tolerance test at rest (OGTT-0). Cardiopulmonary exercise test (CPX) was performed until a respiratory exchange ratio (RER) ≥1.20, beeing anaerobic (CPX-1), followed by OGTT-1. A steady-state CPX of 30-minute duration was performed targeting an RER between 0.90 and 0.95, being aerobic (CPX-2), followed by OGTT-2.

Results

In CPX-1, maximum exercise intensity (maxIntensity) averaged at 99 ± 30 Watt and peak oxygen consumption (VO_2peak) reached 15.9 ± 2.8 ml/min/kg. In CPX-2, aerobic intensity averaged at 29 ± 9 Watt, representing 31% of maxIntensity and 61% of VO_2peak. After aerobic exercise, 2-hour plasma glucose was significantly reduced to an average of 9.4 ± 2.3 mmol/l (P < 0.05). Anaerobic exercise did not reduce 2-hour plasma glucose as compared to OGTT-0 (12.6 ± 2.2 vs 12.6 ± 3.9 mmol/l).

Conclusion

Aerobic exercise intensity was very low in our patients with CHD and T2DM. Postprandial plasma glucose was reduced only by aerobic exercise. Larger studies on the optimal exercise intensity are needed in this patient cohort.

Inter-Individual Variability in Metabolic Syndrome Severity Score and VO2max Changes Following Personalized, Community-Based Exercise Programming

This study sought to examine the effectiveness of a personalized, community-based exercise program at reducing MetS severity and consequently Type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) risk. One-hundred and fifty physically inactive participants (aged 18-83 years) were randomized to a non-exercise control group (n = 75; instructed to continue their usual lifestyle habits) or treatment group (n = 75). Participants randomized to the treatment group completed a 12 week personalized exercise training program based on the American Council on Exercise (ACE) Integrated Fitness Training (IFT) model guidelines. Z-scores were derived from levels of metabolic syndrome risk factors to determine the severity of MetS (MetS z-score). After 12 weeks, the treatment group showed a significant favorable change in MetS z-score, whereas the control group demonstrated increased severity of the syndrome (between-group difference, p < 0.05). The proportion of MetS z-score responders (Δ > -0.48) was greater following the exercise intervention (71%, 50/70) compared to control (10%, 7/72) (between group difference, p < 0.001). The inter-individual variability in VO₂max change also showed a similar trend. These findings provide critical translational evidence demonstrating that personalized exercise programming based upon the ACE IFT model guidelines can be successfully implemented within the community setting to reduce T2DM and CVD risk.

Personalized Moderate-Intensity Exercise Training Combined with High-Intensity Interval Training Enhances Training Responsiveness

This study sought to determine if personalized moderate-intensity continuous exercise training (MICT) combined with high-intensity interval training (HIIT) was more effective at improving comprehensive training responsiveness than MICT alone. Apparently healthy, but physically inactive men and women (n = 54) were randomized to a non-exercise control group or one of two 13-week exercise training groups: (1) a personalized MICT + HIIT aerobic and resistance training program based on the American Council on Exercise guidelines, or (2) a standardized MICT aerobic and resistance training program designed according to current American College of Sports Medicine guidelines. Mean changes in maximal oxygen uptake (VO_2max) and Metabolic (MetS) z-score in the personalized MICT + HIIT group were more favorable (p < 0.05) when compared to both the standardized MICT and control groups. Additionally, on the individual level, there were positive improvements in VO_2max (Δ > 4.9%) and MetS z-score (Δ ≤ -0.48) in 100% (16/16) of participants in the personalized MICT + HIIT group. In the present study, a personalized exercise prescription combining MICT + HIIT in conjunction with resistance training elicited greater improvements in VO_2max, MetS z-score reductions, and diminished inter-individual variation in VO_2max and cardiometabolic training responses when compared to standardized MICT.

Time Course Changes in Confirmed 'True' VO 2 max After Individualized and Standardized Training

This study sought to examine time course changes in maximal oxygen consumption (VO ₂ max) confirmed with verification testing following 12 weeks of standardized vs. individualized exercise training. Participants (N=39) were randomly allocated to differing exercise intensity prescription groups: ventilatory threshold (individualized) or % heart rate reserve (standardized). At baseline, 4, 8, and 12 weeks, participants completed maximal exercise testing with a verification protocol to confirm ‘true VO ₂ max.’ VO ₂ max in the standardized group changed from 24.3±4.6 ml·kg ⁻¹ ·min ⁻¹ at baseline to 24.7±4.6, 25.9±4.7, and 26.0±4.2 ml·kg ⁻¹ ·min ⁻¹ at week 4, 8, and 12, respectively, with a significant difference (p<0.05) in VO ₂ max at week 8 and 12 compared to baseline. The individualized group had increases in VO ₂ max from _{online 2} 9.5±7.5 ml·kg ⁻¹ ·min ⁻¹ at baseline to 30.6±8.4, 31.4±8.4, and 32.8±8.6 ml·kg ⁻¹ ·min ⁻¹ at week 4, 8, and 12, respectively. In the individualized group, there were significant differences (p<0.05) in VO ₂ max from baseline to week 8 and 12 and a significant increase in VO ₂ max from week 8 to 1 _{online 2} . Although not statistically significant, our preliminary data demonstrates a more rapid and potent improvement in VO ₂ max when exercise intensity is individualized. This is the first investigation to employ use of the verification procedure to confirm ‘true VO ₂ max’ changes following exercise training using ventilatory thresholds.

How to Construct, Conduct and Analyze an Exercise Training Study?

Randomized controlled trials (RCTs) can be regarded as gold standard in investigating dose-response and causal relationships in exercise science. Recommendations for exercise training routines and efficacy analyses of certain training regimen require valid data derived from robust RCTs. Moreover, meta-analyses rely on RCTs and both RCTs and meta-analyses are considered the highest level of scientific evidence. Beyond general study design a variety of methodological aspects and notable pitfalls has to be considered. Therefore, exercise training studies should be carefully constructed focusing on the consistency of the whole design "package" from an explicit hypothesis or research question over study design and methodology to data analysis and interpretation. The present scoping review covers all main aspects of planning, conducting, and analyzing exercise based RCTs. We aim to focus on relevant aspects regarding study design, statistical power, training planning and documentation as well as traditional and recent statistical approaches. We intend to provide a comprehensive hands-on paper for conceptualizing future exercise training studies and hope to stimulate and encourage researchers to conduct sound and valid RCTs in the field of exercise training.

Aerobic Fitness of Starter and Non-Starter Soccer Players in the Champion's League

To identify individual response patterns in selected aerobic fitness variables of regular starters (ST; N = 7) and non-starters (Non-ST; N = 10), top level professional soccer players were tested for maximal oxygen uptake (VO2max), velocity at 4 mM of lactate (V4), velocity at maximal oxygen uptake (νVO_2max) and oxygen pulse (O₂-pulse) in July and December following consecutive periods of fixture congestion. V4 was the only variable that increased significantly in December compared to July (15.1 ± 0.5 vs. 14.6 ± 0.5, p = 0.001). There was an almost certain beneficial large mean team change for V4 (ES = 1.2 (0.67; 1.57), 100/0/0), while beneficial mean team changes were less likely for νVO2max and O₂-pulse [ES = 0.31 (-0.08; 0.70), 68/30/2 and ES = 0.24 (0.01; 0.49), 64/36/0, respectively] and unclear for VO_2max (ES = 0.02 (-0.31; 0.70), 18/69/13). With the exception of V4 where 10 out of 17 players (7 ST and 3 Non-ST) showed positive changes higher than the biological variability, all other variables were characterized by a substantial proportion of changes lower than the biological variability. The present study demonstrated that aerobic fitness variables that require maximal effort may be characterized by greater variability of the individual response pattern compared to that of submaximal aerobic fitness variables irrespective of the accumulated game time. Submaximal aerobic fitness variables appear to be more informative in the physiological evaluation of top level soccer players and this may be an advantage during exposure to periods of consecutive games.

The validity of the Moxus Modular metabolic system during incremental exercise tests: impacts on detection of small changes in oxygen consumption

PURPOSE

We investigated the accuracy of the Moxus Modular Metabolic System (MOXUS) against the Douglas Bag Method (DBM) during high-intensity exercise, and whether the two methods agreed when detecting small changes in [Formula: see text] between two consecutive workloads ([Formula: see text]).

METHODS

Twelve trained male runners performed two maximal incremental running tests while gas exchange was analyzed simultaneously by the two systems using a serial setup for four consecutive intervals of 30 s on each test. Comparisons between methods were performed for [Formula: see text], [Formula: see text], fractions of expired O2 (FeO2) and CO2 (FeCO2) and [Formula: see text].

RESULTS

The MOXUS produced significant higher (mean ± SD, n = 54) readings for [Formula: see text] (80 ± 200 mL min(-1), p = 0.005) and [Formula: see text] (2.9 ± 4.2 L min(-1), p < 0.0001), but not FeO2 (-0.01 ± 0.09). Log-transformed 95 % limits of agreement for readings between methods were 94-110 % for [Formula: see text], 97-108 % for [Formula: see text] and 99-101 % for FeO2. [Formula: see text] for two consecutive measurements was not different between systems (120 ± 110 vs. 90 ± 190 mL min(-1) for MOXUS and DBM, respectively, p = 0.26), but agreement between methods was very low (r = 0.25, p = 0.12).

DISCUSSION

Although it was tested during high-intensity exercise and short sampling intervals, the MOXUS performed within the acceptable range of accuracy reported for automated analyzers. Most of the differences between equipments were due to differences in [Formula: see text]. Detecting small changes in [Formula: see text] during an incremental test with small changes in workload, however, might be beyond the equipment's accuracy.

How to test maximal oxygen uptake: a study on timing and testing procedure of a supramaximal verification test

Verification tests are becoming increasingly common for confirming maximal oxygen uptake (VO2 max) attainment. Yet, timing and testing procedures vary between working groups. The aims of this study were to investigate whether verification tests can be performed after an incremental test or should be performed on a separate day, and whether VO2 max can still be determined within the first testing session in subjects not satisfying the verification criterion. Forty subjects (age, 24 ± 4 years; VO2 max, 50 ± 7 mL·min–1·kg–1) performed a maximal incremental treadmill test and, 10 min afterwards, a verification test (VerifDay1) at 110% of maximal velocity (vmax). The verification criterion was a VerifDay1 peak oxygen uptake (VO2 peak) ≤5.5% higher than the incremental test value. Subjects not achieving the verification criterion performed another verification test at 115% vmax (VerifDay1′) 10 min later, trying to confirm VerifDay1 VO2 peak as VO2 max. All other subjects exclusively repeated VerifDay1 on a separate day (VerifDay2). Of the 40 subjects, 6 did not satisfy the verification criterion. In 4 of them, attainment of VO2 max was confirmed by VerifDay1′. VO2 peak was equivalent between VerifDay1 and VerifDay2 (3722 ± 991 mL·min–1 vs. 3752 ± 995 mL·min–1, p = 0.56), whereas time to exhaustion was significantly longer in VerifDay2 (2:06 ± 0:22 min:s vs. 2:42 ± 0:38 min:s, p < 0.001, n = 34). The verification test VO2 peak does not seem to be affected by a preceding maximal incremental test. Incremental and verification tests can therefore be performed within the same testing session. In individuals not achieving the verification criterion, VO2 max can be determined by means of a subsequent, more intense verification test in most but not all cases.

Exercise Training for Heart Failure Patients with and without Systolic Dysfunction: An Evidence-Based Analysis of How Patients Benefit

Significant benefits can be derived by heart failure patients from exercise training. This paper provides an evidence-based assessment of expected clinical benefits of exercise training for heart failure patients. Meta-analyses and randomized, controlled trials of exercise training in heart failure patients were reviewed from a search of PubMed, Cochrane Controlled Trial Registry (CCTR), CINAHL, and EMBASE. Exercise training improves functional capacity, quality of life, hospitalization, and systolic and diastolic function in heart failure patients. Heart failure patients with preserved systolic function (HFnEF) participating in exercise training studies are more likely to be women and are 5–7 years older than their systolic heart failure (CHF) counterparts. All patients exhibit low functional capacities, although in HFnEF patients this may be age related, therefore subtle differences in exercise prescriptions are required. Published works report that exercise training is beneficial for heart failure patients with and without systolic dysfunction.

Intermittent hypoxia does not affect endurance performance at moderate altitude in well-trained athletes

In this study, we examined the effects of a pre-acclimatization programme on endurance performance at moderate altitude using a resting intermittent hypoxia protocol. The time-trial performance of 11 cyclists was determined at low altitude (600 m). Athletes were randomly assigned in a double-blind fashion to the hypoxia or the control group. The pre-acclimatization programme consisted of seven sessions each lasting 1 h in normobaric hypoxia (inspired fraction of oxygen of 12.5%, equivalent to approximately 4500 m) for the hypoxia group (n = 6) and in normoxia (inspired fraction of oxygen of 20.9%) for the control group (n = 5). The time-trials were repeated at moderate altitude (1970 m). Mean power output during the time-trial at moderate altitude was decreased in the hypoxia group (-0.26 +/- 0.11 W x kg(-1)) and in the control group (-0.13 +/- 0.04 W x kg(-1)) compared with at low altitude but did not differ between groups (P = 0.13). Our results suggest that the applied protocol of intermittent hypoxia had no positive effect on endurance performance at moderate altitude. Whether different intermittent hypoxia protocols are advantageous remains to be determined.

Differences in adaptations to 1 year of aerobic endurance training: individual patterns of nonresponse

Lacking responses to endurance training (ET) have been observed for several variables. However, detailed analyses of individuals' responses are scarce. To learn more about the variability of ET adaptations, patterns of response were analyzed for each subject in a 1-year ET study. Eighteen participants [42 ± 5 years, body mass index: 24 ± 3 kg/m(2), maximal oxygen uptake (VO(2max) ): 38 ± 5 mL/min/kg] completed a 1-year jogging/walking program on 3 days/week, 45 min/session at 60% heart rate (HR) reserve. VO(2max), resting HR (rHR), exercise HR (eHR) and individual anaerobic threshold (IAT) were determined by treadmill and cycling ergometry respectively. Intraindividual coefficients of variation were extracted from the literature to distinguish random changes from training responses. Eight participants showed improvements in all variables. In 10 participants, one or two variables did not improve (VO(2max), rHR, eHR and IAT remained unchanged in four, four, three and one cases, respectively). At least one variable improved in each subject. Data indicate that ET adaptations might be detected in each individual using multiple variables of different adaptation levels and intensity domains. Nonresponse seems to occur frequently and might affect all variables. Further studies should investigate whether nonresponders improve with altered training. Furthermore, associations between patterns of nonresponse and health benefits from ET are worth considering.

Respiratory indices by gas analysis and fat metabolism by indirect calorimetry in normal subjects and triathletes

BACKGROUND

The effects of exercise on different indices reflecting the metabolism have been of interest for a long time, and a relationship between anaerobic indices and maximal oxygen uptake has been established. The inter-relationship between different respiratory indices during an exercise test remains to be studied in order to understand differences between individuals. Therefore, the aim of this study was to determine three respiratory indices and investigate their inter-relationship in individuals with highly variable working capacity. A second aim was to investigate the fat metabolism at the VO(2) corresponding to the respiratory compensation point (Pq) in the different subjects using indirect calorimetry.

METHODS

Sixty control subjects (20 female) and 18 triathletes (six female) performed an exercise test with gas analysis. Three respiratory indices, derivative crossing (Dx), point of crossing (Px) and respiratory compensation point (Pq), were calculated using a computerized method. Fat metabolism at Pq was calculated using indirect calorimetry.

RESULTS

Two different sequences of the respiratory indices were found: Dx<Px<Pq and Dx<Pq<Px. In subjects whom Px occurred before Pq, no fat metabolism was seen at Pq, whilst in subjects with Pq occurring before Px, a combined aerobic fat metabolism and anaerobic carbohydrate metabolism was found at Pq.

CONCLUSION

This study has shown two different sequences of the respiratory indices Dx, Px and Pq in subjects of varying working capacity. The individual differences in the order of occurrence of Px and Pq during the exercise test are most likely caused by different abilities to metabolize fat at high workloads.

Time course of changes in endurance capacity: a 1-yr training study

PURPOSE

To investigate the magnitude and the time course of changes in endurance capacity during the first year of an aerobic endurance training program with constant HR prescription.

METHODS

Eighteen previously untrained subjects (7 males and 11 females, 42 +/- 5 yr, BMI of 24.3 +/- 2.5 kg x m(-2), and maximal oxygen uptake (VO(2max)) of 37.7 +/- 4.6 mL x min(-1) x kg(-1)) completed a 12-month jogging/walking program on 3 d x wk(-1) 45 min per session with a constant HR prescription of 60% HR reserve. Exhaustive treadmill tests were conducted before the intervention and after 3, 6, 9, and 12 months of training. In addition, submaximal tests on an indoor running track were performed every 4 wk.

RESULTS

After 12 months, VO(2max) had increased by 0.36 +/- 0.33 L x min(-1) (median [interquartile range]: 16% [9%-20%], P < 0.001). After 3, 6, and 9 months, 52%, 65%, and 79% of this increase were reached, respectively. Resting HR decreased by a total of 9 +/- 6 min(-1) (P<0.001). Of this change, 47% and 102% had occurred after 3 and 6 months, respectively. Submaximal exercise HR during the treadmill tests decreased by 11 +/- 7 min(-1) (P < 0.001) on average. After 3 and 6 months of training, 93% and 101% of this change were observed, respectively. The running track tests revealed that submaximal exercise HR did not change significantly after the ninth week of training.

CONCLUSIONS

Beginners in recreational endurance exercise are advised to increase their training stimulus after 6 months of training to maintain training effectiveness because no further significant changes in endurance capacity were observed thereafter. When planning future endurance training studies in untrained subjects, it should be taken into account that submaximal exercise HR might reflect endurance changes during the first week only, whereas VO(2max) remains responsive after several months.

Criteria for determination of maximal oxygen uptake: a brief critique and recommendations for future research

Although the concept of maximal oxygen uptake (V-dotO(2max)) was conceived as early as 1923, the criteria used to establish whether a true V-dotO(2max) has been attained have been heavily criticised. Consequently, an improvement in the methodology of the existing criteria, or development of new criteria, is required. In order to be valid across experimental studies, new or improved criteria need to be independent of exercise modality, test protocol and subject characteristics. One procedure that has shown potential for yielding valid V-dotO(2max) criteria is the verification phase, which consists of a supramaximal constant speed run to exhaustion performed after the incremental phase of a V-dotO(2max) test. A peak oxygen uptake (V-dotO(2peak)) in the verification phase that is similar (within the tolerance of measurement error, e.g. within 2%) to the V-dotO(2max) value attained in the incremental phase would indicate that a true V-dotO(2max) has been elicited. Verification of the maximal heart rate would also indicate that a subject has given a maximum effort. Although the validity of the present methodology for identifying an oxygen uptake (V-dotO(2)) plateau is questionable, a V-dotO(2) plateau criterion based on the individual slope of the V-dotO(2)-work-rate relationship should improve its validity. This approach also allows determination of the 'total V-dotO(2) plateau', which is in contrast to currently used V-dotO(2) plateau criteria that are based on the difference in V-dotO(2) between only two test stages or V-dotO(2) data points. The ratings of perceived exertion scale has been criticised for being a one-dimensional measure of physical effort and V-dotO(2max) criteria based on a multidimensional psychophysiological approach should increase validity. Visual analogue scales can be used to assess aspects such as muscular pain, determination and overall perceived effort. Furthermore, they are easy to complete and have demonstrated good reliability and validity in clinical and health settings. Future research should explore these and other potential approaches to developing new or improved V-dotO(2max) criteria, so that, ultimately, a standardised set of V-dotO(2max) criteria can be established. At present, however, the greatest challenge is identifying V-dotO(2max) criteria that remain valid across studies.

The impact of preoperative micronutrient supplementation in lung surgery. A prospective randomized trial of oral supplementation of combined alpha-ketoglutaric acid and 5-hydroxymethylfurfural

OBJECTIVE

Preoperative micronutrient supplementation in fast-track surgery programs have shown to reduce complications, shorten recovery, and thereby lower costs. In a prospective randomized study, the metabolic effects of a combination of alpha-ketoglutaric acid (alpha-KG) and 5-hydroxymethylfurfural (5-HMF) were evaluated concerning their impact on improvement of exercise capacity and reduction of oxidative stress in lung surgery.

METHODS

Thirty-two consecutive patients admitted for lung resection due to NSCLC were randomized to the study protocol. All patients received preoperative nutritional guidelines according to general recommendations. In 16 (study group), a supplementation of 7.2g alpha-KG and 720 mg 5-HMF/day (SANOPAL) was administered from days 1 to 10. Spiroergometric evaluation was carried out at baseline and day 10 after micronutrient supplementation. Blood samples for the determination of oxidative stress, i.e. carbonyl proteins (CPs) and isoprostanes (IPs) were taken on at baseline, in the operating room just before resection treatment, and 25 min after single lung ventilation (SLV).

RESULTS

Spiroergometric re-evaluation showed a significant increase of VO2max (p=0.0108) and Watt's (p=0.011) in favor of the study group. Determination of oxidative stress showed a significant reduction of CPs before (p=0.048) and after SLV (p=0.0001) for the study group compared to the control group. The same is true for IPs before (p=0.003) and after SLV (p=0.02). Hospitalization and intensive care unit (ICU) of the study group showed a significant reduction compared to the control group (p=0.03 and p=0.02, respectively).

CONCLUSIONS

Simple oral supplementation using a combination of alpha-KG and 5-HMF of preoperative micronutrition may therefore be one further step in a multimodality approach of fast-track surgery programs also in lung surgery.

Psychological symptoms in patients after surgery for congenital cardiac disease

AIMS

We studied a population of patients with surgically corrected congenital cardiac disease to determine whether limitations in activity, impaired cardiac performance, and perception of body image have effects on psychological symptoms.

METHODS

We undertook medical examinations, and carried out standardized interviews, in 361 patients aged between 14 and 45 years with surgically corrected congenital cardiac disease. From this data, findings from 343 patients were suitable for analysis. Subjectively reported limitations in activity were classified according to the system proposed by the New York Heart Association, while cardiopulmonary capacity was used as the indicator of cardiac performance. The Brief Symptom Inventory was used for assessing psychological symptoms, such as somatization, obsession-compulsion, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, and psychoticism. The Body Image Questionnaire was used to depict attitudes towards body image, which is assessed on the two subscales of rejection of the body and vitality. Multivariate regression analyses were conducted separately for females and males, taking into account age and socio-economic position.

RESULTS

Impairments of everyday activities had only a few substantial associations with psychological symptoms. No significant effects of cardiac functional capacity as a standardized physiological measure emerged. Psychological symptoms were strongly influenced by perceptions of body image, particularly if they rejected it, this holding particularly for males. There were no gender differences in terms of psychological symptoms.

CONCLUSIONS

Limitations of activity, and impaired cardiac performance, have only minor effects on psychological symptoms in patients with surgically corrected congenital cardiac disease. The perception of body image was the strongest predictor, especially if patients rejected their body as a result of disfigurement or perceived deficiency.