The Acute Impact of Endurance Exercise on Right Ventricular Structure and Function: A Systematic Review and Meta-analysis

There have been many studies since the late 1980s investigating the effect of endurance exercise on the left ventricle. More recently, attention has shifted to the right heart, with suggestions that endurance exercise may have a detrimental effect on the right ventricle. This systematic review and meta-analysis summarizes and critiques 26 studies, including 649 athletes, examining the acute impact of endurance exercise on the right ventricle. We also present a subanalysis contrasting ultraendurance with endurance exercise. Finally, we identify areas for future research, such as the influence of sex, ethnicity, and age.

Energetically optimal stride frequency is maintained with fatigue in trained ultramarathon runners

OBJECTIVES

At a given running speed, humans naturally endeavor to achieve an optimal stride frequency that minimizes metabolic cost. Research has suggested that runners select this near optimal stride frequency in some process of self-optimization even during fatiguing tasks up to 1-h of high-intensity running. Here, we studied whether runners demonstrate a similar self-optimizing capability after an ultramarathon of 6 h.

DESIGN

Controlled pre-post study.

METHOD

We collected temporal stride kinematics and metabolic data in nine (experimental group) male runners before and after 6 h of running and in six (control group) male ultramarathon runners who did not run, but stayed awake and performed normal, daily physical activities avoiding strenuous exercises over the 6-h period. For each participant, preferred and optimal stride frequencies were measured, where stride frequency was systematically varied above and below PSF (±4% and ±8%).

RESULTS

Preferred and optimal stride frequencies across time and group showed no significant differences (p ≥ 0.276). Furthermore, neither the overall relationship between metabolic cost and stride frequency, nor the energetically optimal stride frequency changed substantially after several hours of running.

CONCLUSIONS

Similar dynamics of stride frequency adjustments in the experimental group occurred as those found in a non-fatigued state. This suggests that after an ultramarathon of 6 h, runners were still able to optimize their gait, and automatically adjust it in order to converge on the energetically optimal gait.

Physiological responses to a five-day adventure race: Continuous blood glucose, hemodynamics and metabolites the 2012 GODZone field-study

Background/Objective

Adventure racing is an ultra-endurance activity that imposes a unique multifaceted stress on the human body. The purpose of this field study was to examine the physiological responses to a 5-day adventure race.

Methods

Eight competitors, two teams (1 female each) in the 2012 GODZone adventure race volunteered. Competitors trekked, cycled and paddled ∼326 km in ∼116 hours. Continuous glucose was measured the day before and throughout. Body mass, urinary solutes, and blood pressure and heart rate during resting, standing, and repeated squat-stand conditions, were assessed pre and post.

Results

Despite no changes in mean blood glucose levels, there was increased glycemic variability (Standard deviation glucose; Pre: 0.5 ± 0.1 vs Race: 1.0 ± 0.2 mmol/L, p = 0.02) and periods of hypoglycemia (i.e., Min glucose Pre: 4.1 ± 0.3 vs Race: 3.6 ± 0.5 mmol/L, p = 0.05) during the race. After the race, the blood pressure during resting, standing and squat-stand conditions was significantly lower, by 14 ± 14 mmHg, 16 ± 15 mmHg and 18 ± 15 mmHg (all p < 0.05), respectively, with no change in heart rate. During five-days of adventure racing there is increased glycemic variability and more frequent periods of low blood glucose levels. Additionally, following the race pronounced hypotension is observed in competitors.

Conclusion

We observed more frequent glucose fluctuations, lower glucose levels and significant perturbations in blood pressure control. Further research is warranted to examine the long-term impact of adventure racing on metabolic and cardiovascular function.

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Five-days of adventure racing can cause blood pressure pertubations.

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Adventure racing results in fluctuations of blood glucose.

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There are periods of hypoglycemia during an adventure race which maynot be captured by pre-post- measures.

Psychophysiological response of air mobile protection teams in an air accident manoeuvre

Different extreme contexts elicit a stress response on human body, specifically on combat produces an increase of sympathetic nervous system and a direct effect on the organic response. This research aimed to study the psychophysiological response of an air security force in a simulated air accident in a hostile area and its subsequent subterfuge to a safe area. We analyzed 13 soldiers (32.4 ± 8.0 years) from an air security force unit of the Spanish Air Force who were divided into three teams to conduct the manoeuvre. We analyzed before and after the manoeuvre psychological well-being scale, personal views survey, recovery-stress questionnaire (REST-52 Sport); heart rate variability, visual analogue scale, rated of perceived exertion, spirometry, hydration and hand strength were analyzed during the four days of the manoeuvre: This produced a significantly (p < .05) increase in sympathetic modulation, hand strength, dehydration status, general and specific stress from RESTQ-52. With this data we can conclude that an air accident manoeuvre of three nights and four days causes in the air mobile protection team a high sympathetic nervous system modulation, increases on muscle strength manifestations and stress and a dehydration status.

Fluid retention, muscle damage, and altered body composition at the Ultraman triathlon

PURPOSE

The primary purpose of this investigation was to determine the effects of participation in a 3-day multistage ultraendurance triathlon (stage 1 = 10 km swim, 144.8 km bike; stage 2 = 275.4 km bike; stage 3 = 84.4 km run) on body mass and composition, hydration status, hormones, muscle damage, and blood glucose.

METHODS

Eighteen triathletes (mean ± SD; age 41 ± 7.5 years; height 175 ± 9 cm; weight 73.5 ± 9.8 kg; male n = 14, female n = 4) were assessed before and after each stage of the race. Body mass and composition were measured via bioelectrical impedance, hydration status via urine specific gravity, hormones and muscle damage via venous blood draw, and blood glucose via fingerstick.

RESULTS

Following the race, significant changes included reductions in body mass (qualified effect size: trivial), fat mass (moderate), and percent body fat (small); increases in percent total body water (moderate) and urine specific gravity (large); and unchanged absolute total body water and fat-free mass. There were also extremely large increases in creatine kinase, C-reactive protein, aldosterone and cortisol combined with reductions in testosterone (small) and the testosterone:cortisol ratio (moderate). There were associations between post-race aldosterone and total body water (r = -0.504) and changes in cortisol and fat-free mass (r = -0.536). Finally, blood glucose increased in a stepwise manner prior to each stage.

CONCLUSIONS

Participation in Ultraman Florida leads to fluid retention and dramatic alterations in body composition, muscle health, hormones, and metabolism.