RESEARCH: studies I shared this week: 14 to 20 November 2022

All of the studies I've shared (~500 studies) are available on the RESOURCES PAGE.

PHYSIOLOGY: Myocardial Fibrosis and Coronary Calcifications Caused by Endurance Exercise?

STUDY DETAILS -

1. To compare the prevalence of myocardial fibrosis and coronary calcification in individuals who have performed very high levels of strenuous endurance exercise (SEE) (former male professional cyclists) and sex/age-matched controls.
2. We used a cross-sectional (case-control) observational design, where cases were former finishers of ≥1 Grand Tour (Tour de France, Giro d’ Italia or Vuelta a España) and controls were untrained individuals free of cardiovascular risk.
3. Fibrotic patches were evidenced only in the left ventricle (LV), with a higher prevalence in cases.
4. However, fibrotic tissue was non-ischemic and of low extension (0.6 ± 0.4% of LV mass), and no significant differences were found between cases and controls for native T1 or T2 values.
5. Sub-analyses revealed no differences attending to whether cases were still performing regular SEE (n = 8) or not (n = 15) after professional retirement.
6. Although former professional cyclists seemed to show a greater prevalence of myocardial fibrosis, the extension of fibrotic tissue was minimal and no alterations were found in coronary calcification indicators.

PRACTICAL TAKEAWAY - there do not appear to be major cardiac maladaptations with long-term exposure to strenous endurance exercise.

PHYSIOLOGY: The impact of oral health on physical fitness

STUDY DETAILS -

1. In this review, we aimed to systematically review the available evidence to assess the effect of oral health on general physical fitness.
2. Ten articles suggested a correlation between dental and oral condition toward physical fitness, body balance, cardiorespiratory function, and also cognitive function.
3. This review suggests that there is a negative effect of poor dental and/or oral health on physical fitness and performance.

PRACTICAL TAKEAWAY - look after your teeth and dental health.

PHYSIOLOGY: Physiological differences between sprint and distance-specialized cross-country skiers

STUDY DETAILS -

1. This study aimed to identify the possible anthropometric and physiological differences between elite male sprint and distance skiers
2. Measurements included submaximal O2 cost (5°, 3m/s) and a 1000-m time trial (6°, >3.25 m/s) to assess VO2peak and accumulated oxygen (∑O2) deficit.
3. The groups displayed similar O2 cost during the submaximal load.
4. The sprint skiers had a higher ∑O2 deficit and VO2peak in absolute values, while VO2peak relative to body mass was lower than in the distance skiers.
5. The sprint skiers were heavier than the distance skiers, taller, and had a higher body-mass index.
6. An interesting finding was that Hb mass relative to body mass tended to be higher in the distance skiers.

PRACTICAL TAKEAWAY - "Elite male sprint skiers have both higher absolute anaerobic capacity and higher maximal aerobic power than elite distance skiers. However, distance skiers have higher maximal aerobic power relative to body mass."

INTERVALS: Similar Time Near VO2max Regardless of Work Rate Manipulation in Cycling Interval Training

STUDY DETAILS -

1. The current study aimed to compare time spent above 90% V̇O2max (tV̇O2max) during 3 work-matched interval training protocols comprising 8×60-second exercise efforts with decreasing, increasing, or constant work rate distribution within each exercise interval.
2. Three work-matched interval training sessions comprising 8×60 s efforts: 60 s active recovery with the power output held constant (100%Pmax; ITCON), decreasing (from 110 to 90%Pmax; ITDEC), or increasing (from 90 to 110%Pmax; ITINC) linearly throughout each work interval.
3. The time sustained above 90% of V̇O2max, time sustained above 90% of HRmax, blood lactate concentrations, and final RPE were similar among protocols.
4. Work-matched interval training induced similar time near V̇O2max and associated physiological responses regardless of work rate manipulation.

PRACTICAL TAKEAWAY - it doesn't seem to matter if your effort within intervals is not perfectly even as long as the work-rate achieves the stimulus.

PHYSIOLOGY: Variability in energy expenditure is much greater in males than females

STUDY DETAILS -

1. We analyzed a large database on energy expenditure in adult humans (1494 males and 3108 females) to investigate whether humans have evolved sex differences in the degree of interindividual variation in energy expenditure.
2. We found that, even when statistically comparing males and females of the same age, height, and body composition, there is much more variation in total, activity, and basal energy expenditure among males.
3. The considerably greater male variation in basal energy expenditure is remarkable and may be explained, at least in part, by greater male variation in the size of energy-demanding organs.

PRACTICAL TAKEAWAY - it is important to consider individual energy expenditure and energy needs when considering nutrition prescriptions.

PHYSIOLOGY: Stabilising function of the human diaphragm in response to involuntary augmented breaths induced with or without lower-limb movements

STUDY DETAILS -

1. Our aim was to test whether the stabilising function of the diaphragm would be altered differentially in response to involuntary augmented breaths induced with or without lower-limb movements.
2. At equivalent levels of tidal volume and minute ventilation, mean inspiratory transdiaphragmatic pressure (TPDI) was consistently higher during exercise compared with CO2-rebreathe due to larger increases in gastric pressure and the passive component of TDPI (i.e., mechanical output due to static contractions), and yet diaphragm excursion was consistently lower.
3. This lower excursion during exercise was accompanied by a reduction in excursion time with no difference in the active component of TDPI.
4. Consequently, the rates of increase in excursion velocity (excursion/time) and power output (active TDPI × velocity) did not differ between the two tasks.

PRACTICAL TAKEAWAY - the diaphragm performs two functions: respiration and stabilisation. It is able to adapt to the demands of exercise stabilisation to ensure that respiration demands are not impacted.