Arja Uusitalo

Altered oxidative stress in overtrained athletes

Abstract The purpose of the present study was to examine the relationship between oxidative stress and overtraining syndrome. Indicators of oxidative stress (plasma protein carbonyls, nitrotyrosine, and malondialdehyde) and antioxidant status (oxygen radical absorbance capacity) were measured in severely overtrained (two women, five men) and control athletes (five women, five men). Samples were collected from both groups at baseline (i.e. in the overtraining state of overtrained athletes) and after 6 months of recovery, both at rest and immediately after an exercise test to volitional exhaustion. At baseline, overtrained athletes had higher plasma protein carbonyls at rest than controls (mean difference 0.03 nmol · mg−1, 95% CI = 0.01–0.05 nmol · mg−1, P = 0.003, effect size = 0.40). Both at baseline and after recovery, exercise to exhaustion led to an increase in oxygen radical absorbance capacity and malondialdehyde (P = 0.001–0.006) in the controls but not in the overtrained athletes. Furthermore, at baseline, only overtrained athletes showed negative correlations between oxygen radical absorbance capacity at rest and protein carbonyls after exhaustive exercise (r = −0.98, P = 0.0001). These results suggest that increased oxidative stress has a role in the pathophysiology of overtraining syndrome. The attenuated responses of oxidative stress and antioxidant capacity to exercise in the overtrained state could be related to an inability to perform exercise effectively and impaired adaptation to exercise.

Serum sex hormone-binding globulin and cortisol concentrations are associated with overreaching during strenuous military training.

Tanskanen, MM, Kyröläinen, H, Uusitalo, AL, Huovinen, J, Nissilä, J, Kinnunen, H, Atalay, M, and Häkkinen, K. Serum sex hormone-binding globulin and cortisol concentrations are associated with overreaching during strenuous military training. J Strength Cond Res 25(3): 787-797, 2011-The purpose was (a) to study the effect of an 8-week Finnish military basic training period (BT) on physical fitness, body composition, mood state, and serum biochemical parameters among new conscripts; (b) to determine the incidence of overreaching (OR); and (c) to evaluate whether initial levels or training responses differ between OR and noOR subjects. Fifty-seven males (19.7 ± 0.3 years) were evaluated before and during BT. Overreaching subjects had to fulfill 3 of 5 criteria: decreased aerobic physical fitness (&OV0312;O2max), increased rating of perceived exertion (RPE) in 45-minute submaximal test at 70% of &OV0312;O2max or sick absence from these tests, increased somatic or emotional symptoms of OR, and high incidence of sick absence from daily service. &OV0312;O2max improved during the first 4 weeks of BT. During the second half of BT, a stagnation of increase in &OV0312;O2max was observed, basal serum sex hormone-binding globulin (SHBG) increased, and insulin-like growth factor-1 and cortisol decreased. Furthermore, submaximal exercise-induced increases in cortisol, maximum heart rate, and postexercise increase in blood lactate were blunted. Of 57 subjects, 33% were classified as OR. They had higher basal SHBG before and after 4 and 7 weeks of training and higher basal serum cortisol at the end of BT than noOR subjects. In addition, in contrast to noOR, OR subjects exhibited no increase in basal testosterone/cortisol ratio but a decrease in maximal La/RPE ratio during BT. As one-third of the conscripts were overreached, training after BT should involve recovery training to prevent overtraining syndrome from developing. The results confirm that serum SHBG, cortisol, and testosterone/cortisol and maximal La/RPE ratios could be useful tools to indicate whether training is too strenuous.

Association of Military Training with Oxidative Stress and Overreaching

UNLABELLED We hypothesized that increased oxidative stress and disrupted redox balance may be predisposing factors and markers for overreaching (OR). PURPOSE The studys purpose was to examine whether oxidative stress markers and antioxidant status and physical fitness are related to OR during an 8-wk military basic training (BT) period. METHODS Oxidative stress and antioxidant status were evaluated in the beginning and after 4 and 7 wk of training in 35 males (age = 19.7 ± 0.3 yr) at rest and immediately after a 45-min submaximal exercise. Physical activity (PA) was monitored by an accelerometer throughout BT. Indicators of OR were also examined. RESULTS From baseline to week 4, increased daytime moderate to vigorous PA led to concomitant decreases in the ratio of oxidized to total glutathione (GSSG/TGSH) and GSSG. After 4 wk of BT, GSSG/TGSH and GSSG returned to the baseline values at rest, whereas PA remained unchanged. At every time point, acute exercise decreased TGSH and increased GSSG and GSSG/TGSH, whereas a decrease was observed in antioxidant capacity after 4 wk of training. In the beginning of BT, OR subjects (11 of the 35 males) had higher GSSG, GSSG/TGSH, and malondialdehyde (a marker of lipid peroxidation) at rest (P < 0.01-0.05) and lower response of GSSG and GSSG/TGSH ratio (P < 0.01) to exercise than non-OR subjects. Moreover, OR subjects had higher PA during BT than non-OR (P < 0.05). CONCLUSIONS The sustained training load during the last 4 wk of BT led to oxidative stress observable both at rest and after submaximal exercise. Increased oxidative stress may be a marker of insufficient recovery leading possibly to OR.

Aerobic fitness, energy balance, and body mass index are associated with training load assessed by activity energy expenditure.

The present study examined whether activity energy expenditure related to body mass (AEE/kg) is associated with maximal aerobic fitness (VO2max), energy balance, and body mass index (BMI) during the 2 hardest weeks of the military basic training season (BT). An additional purpose was to study the accuracy of the pre‐filled food diary energy intake. Energy expenditure (EE) with doubly labeled water, energy intake (EI), energy balance, and mis‐recording was measured from 24 male conscripts with varying VO2max. AEE/kg was calculated as (EE × 0.9−measured basal metabolic rate)/body mass. The reported EI was lower (P<0.001) than EE (15.48 MJ/day) and mis‐recording of the pre‐filled diary was −20%. The negative energy balance (−6±26%) was non‐significant; however, the variation was high. The subjects with a low VO2max, a high BMI, and a negative energy balance were vulnerable to low AEE/kg. However, in the multivariate regression analysis only BMI remained in the model, explaining 33% of the variation in AEE/kg. During wintertime BT, AEE/kg is affected by energy balance, VO2max, and BMI. From these three factors, overweight limits high‐level training the most. Furthermore, an optimal energy balance facilitates physical performance and enables high training loads to be sustained during the BT season.

Heart rate variability changes at 2400 m altitude predicts acute mountain sickness on further ascent at 3000–4300 m altitudes

Objective: If the body fails to acclimatize at high altitude, acute mountain sickness (AMS) may result. For the early detection of AMS, changes in cardiac autonomic function measured by heart rate variability (HRV) may be more sensitive than clinical symptoms alone. The purpose of this study was to ascertain if the changes in HRV during ascent are related to AMS. Methods: We followed Lake Louise Score (LLS), arterial oxygen saturation at rest (R-SpO2) and exercise (Ex-SpO2) and HRV parameters daily in 36 different healthy climbers ascending from 2400 m to 6300 m altitudes during five different expeditions. Results: After an ascent to 2400 m, root mean square successive differences, high-frequency power (HF2 min) of HRV were 17–51% and Ex-SpO2 was 3% lower in those climbers who suffered from AMS at 3000 to 4300 m than in those only developing AMS later (≥5000 m) or not at all (all p < 0.01). At the altitude of 2400 m RMSSD2 min ≤ 30 ms and Ex-SpO2 ≤ 91% both had 92% sensitivity for AMS if ascent continued without extra acclimatization days. Conclusions: Changes in supine HRV parameters at 2400 m were related to AMS at 3000–4300 m Thus, analyses of HRV could offer potential markers for identifying the climbers at risk for AMS.

Altered relationship between R-R interval and R-R interval variability in endurance athletes with overtraining syndrome.

Autonomic dysfunction decreases within‐subject correlation between R‐R interval length (RRi) and vagally mediated RRi variability in cardiac disease. We tested the hypothesis that overtraining syndrome (OTS) may also weaken this relationship. Nine OTS and 10 control endurance athletes underwent 24‐h electrocardiogram monitoring, which was repeated in eight OTS and nine control athletes after 6 months, when two OTS athletes still had symptoms of OTS. The power of high‐frequency (HF) oscillations of RRi was analyzed in 5‐min epochs over the whole recording. Quadratic regression was performed between 5‐min values of RRi and log‐transformed (ln) HF to obtain R2 for each recording. The relationship between RRi and HFln was higher in the OTS athletes than controls [R2: 0.87 (90% confidence interval, CI: 0.84–0.89) vs 0.78 (90% CI: 0.72–0.84); P = 0.034; effect size = 1.22]. Large decrease in R2 was observed in six recovered OTS athletes after 6 months follow‐up [ΔR2: −0.12 (90% CI: −0.25–0.01); P = 0.11; effect size = 1.44] with no changes in the controls. Mean values of RRi and its variability did not differ between the groups. The within‐subject correlation between RRi and vagally mediated RRi variability was stronger in endurance athletes with OTS compared with controls. The present findings may improve the detection of OTS and recovery from OTS in endurance athletes.

Cardiovascular Autonomic Nervous System Function and Aerobic Capacity in Type 1 Diabetes

Impaired cardiovascular autonomic nervous system (ANS) function has been reported in type 1 diabetes (T1D) patients. ANS function, evaluated by heart rate variability (HRV), systolic blood pressure variability (SBPV), and baroreflex sensitivity (BRS), has been linked to aerobic capacity (VO2peak) in healthy subjects, but this relationship is unknown in T1D. We examined cardiovascular ANS function at rest and during function tests, and its relations to VO2peak in T1D individuals. Ten T1D patients (34 ± 7 years) and 11 healthy control (CON; 31 ± 6 years) age and leisure-time physical activity-matched men were studied. ANS function was recorded at rest and during active standing and handgrip. Determination of VO2peak was obtained with a graded cycle ergometer test. During ANS recordings SBPV, BRS, and resting HRV did not differ between groups, but alpha1 responses to maneuvers in detrended fluctuation analyses were smaller in T1D (active standing; 32%, handgrip; 20%, medians) than in CON (active standing; 71%, handgrip; 54%, p < 0.05). VO2peak was lower in T1D (36 ± 4 ml kg−1 min−1) than in CON (45 ± 9 ml kg−1 min−1, p < 0.05). Resting HRV measures, RMSSD, HF, and SD1 correlated with VO2peak in CON (p < 0.05) and when analyzing groups together. These results suggest that T1D had lower VO2peak, weaker HRV response to maneuvers, but not impaired cardiovascular ANS function at rest compared with CON. Resting parasympathetic cardiac activity correlated with VO2peak in CON but not in T1D. Detrended fluctuation analysis could be a sensitive detector of changes in cardiac ANS function in T1D.

Effects of easy-to-use protein-rich energy bar on energy balance, physical activity and performance during 8 days of sustained physical exertion.

Background Previous military studies have shown an energy deficit during a strenuous field training course (TC). This study aimed to determine the effects of energy bar supplementation on energy balance, physical activity (PA), physical performance and well-being and to evaluate ad libitum fluid intake during wintertime 8-day strenuous TC. Methods Twenty-six men (age 20±1 yr.) were randomly divided into two groups: The control group (n = 12) had traditional field rations and the experimental (Ebar) group (n = 14) field rations plus energy bars of 4.1 MJ•day−1. Energy (EI) and water intake was recorded. Fat-free mass and water loss were measured with deuterium dilution and elimination, respectively. The energy expenditure was calculated using the intake/balance method and energy availability as (EI/estimated basal metabolic rate). PA was monitored using an accelerometer. Physical performance was measured and questionnaires of upper respiratory tract infections (URTI), hunger and mood state were recorded before, during and after TC. Results Ebar had a higher EI and energy availability than the controls. However, decreases in body mass and fat mass were similar in both groups representing an energy deficit. No differences were observed between the groups in PA, water balance, URTI symptoms and changes in physical performance and fat-free mass. Ebar felt less hunger after TC than the controls and they had improved positive mood state during the latter part of TC while controls did not. Water deficit associated to higher PA. Furthermore, URTI symptoms and negative mood state associated negatively with energy availability and PA. Conclusion An easy-to-use protein-rich energy bars did not prevent energy deficit nor influence PA during an 8-day TC. The high content of protein in the bars might have induced satiation decreasing energy intake from field rations. PA and energy intake seems to be primarily affected by other factors than energy supplementation such as mood state.

A Comment on: Prevention, diagnosis and treatment of the overtraining syndrome

The Scientific Community of Sports and Exercise Medicine and Sport Sciences should be delighted to see the first Position Statement of Overtraining, which should be our guideline in the field of overtraining research in the nearest future. The topic has for many decades been one of the most interesting fields in Sports Medicine, not least because it is very difficult to study and include all of human physiology. The statement points this out, like do the many previous reviews (references in the statement). Because of this, and also because of missing statements of terminology and diagnostic criteria of overtraining, the previous studies may be difficult to interpret. Classifying the subjects into the different states (i.e. overtraining states, Figure 1 in the statement) of the ‘overtraining’ process may be difficult. The key, as mentioned in the statement, should be recovery time rather than the actual symptoms, which may be similar in the different overtraining states. In addition, defining the difference between the terms overtraining and overtraining syndrome is a good clarification. Overtraining is a process, but overtraining syndrome is an end point it leads to. However, there are some points in the position statement that I would like to comment on. The first is the definitions of overtraining terminology. As we know, we should now be able to lean on this statement when planning our research projects in overtraining and diagnosing patients, so that future research would be more consistent in its terminology and findings. Therefore, I would have hoped that the terminology of the position statement would have been strict in its definitions and recovery time limits in overreaching and the overtraining syndrome. Definitions (diagnostic criteria) are always enlightened agreements of the best experts in the field, and can be changed later if the future scientific data recommends it. However, even after the first position statement of overtraining, future research will be still lost in its definitions. Before, the scientific literature has spoken about the 2 3-week recovery time limit in overreaching, and longer recovery times would refer to the overtraining syndrome. I suppose that this limit could be suitable for differentiating functional and non-functional overreaching, but what is the limit for non-functional overreaching and overtraining syndrome (we may see months in both definitions)? Secondly, one difficulty concerning recovery times, which the statement did not take into consideration at all, is detraining. This is the problem especially when using physical performance parameters as markers of recovery time. After time periods longer than 2 3 weeks, detraining will take place, and it is difficult to differentiate the influence of overtraining and detraining. Therefore, I would still lean more on the recovery of symptoms and subjective feelings of an athlete, or even on a mental stress test (Hynynen et al., 2006) as a marker of real recovery time. Naturally, the time it takes to return back to competition and the previous performance level tells us much about the preceding state of the athlete. However, the reasons for not returning back to competition may also vary. The athlete may be loaded with secondary (or sometimes even primary) mental problems taking away his/her motivation to do sport, or he/she may be afraid to do sport any more (we have no scientific data of this). Sometimes

Changes in cytokines, leptin, and IGF-1 levels in overtrained athletes during a prolonged recovery phase: A case-control study

ABSTRACT We investigated how cytokines are implicated with overtraining syndrome (OTS) in athletes during a prolonged period of recovery. Plasma IL-6, IL-10, TNF-α, IL-1β, adipokine leptin, and insulin like growth factor-1 (IGF-1) concentrations were measured in overtrained (OA: 5 men, 2 women) and healthy control athletes (CA: 5 men, 5 women) before and after exercise to volitional exhaustion. Measurements were conducted at baseline and after 6 and 12 months. Inflammatory cytokines did not differ between groups at rest. However, resting leptin concentration was lower in OA than CA at every measurement (P < 0.050) but was not affected by acute exercise. Although IL-6 and TNF-α concentrations increased with exercise in both groups (P < 0.050), pro-inflammatory IL-1β concentration increased only in OA (P < 0.050) and anti-inflammatory IL-10 was greater in CA (P < 0.001). In OA, exercise-related IL-6 and TNF-α induction was enhanced during the follow-up (P < 0.050). IGF-1 decreased with exercise in OA (P < 0.050); however, no differences in resting IGF-1 were observed. In conclusion, low leptin level at rest and a pro-inflammatory cytokine response to acute exercise may reflect a chronic maladaptation state in overtrained athletes. In contrast, the accentuation of IL-6 and TNF-α responses to acute exercise seemed to associate with the progression of recovery from overtraining.