RESEARCH: studies I shared this week: 1 to 7 August 2022

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

SLEEP: Insufficient sleep undermines dietary efforts to reduce adiposity

PRACTICAL TAKEAWAYS -

1. 14 days of moderate caloric restriction with 8.5 or 5.5 hours of nighttime sleep opportunity.
2. Sleep curtailment decreased the proportion of weight lost as fat by 55% (1.4 vs. 0.6 kg with 8.5 vs. 5.5 hours of sleep opportunity, respectively) and increased the loss of fat-free body mass by 60% (1.5 vs. 2.4 kg)
3. Lack of sufficient sleep may compromise the efficacy of typical dietary interventions for weight loss and related metabolic risk reduction.

CHO: Comparing Acute, High Dietary Protein and Carbohydrate Intake on Transcriptional Biomarkers, Fuel Utilisation and Exercise Performance in Trained Male Runners

PRACTICAL TAKEAWAYS -

1. A 7-day isocaloric high protein diet significantly compromised high intensity exercise performance in trained runners with no real benefit on gene markers of training adaptation.
2. A significant increase in fat oxidation during submaximal exercise was observed post PRO intervention, but this returned to pre levels once the habitual diet was re-introduced, suggesting that the response was driven via fuel availability rather than cellular adaptation.
3. A short-term high protein, low carbohydrate diet in combination with endurance training is not preferential for endurance running performance.

HRV: Does Heart Rate Variability Biofeedback Enhance Executive Functions Across the Lifespan?

PRACTICAL TAKEAWAYS -

1. Fifty-six percent of the studies included in this review reported significant positive effects of HRV-BF intervention on at least one EF. Attention was the domain that most often benefited from the intervention.
2. The majority of EF improvements (78%) occurred in studies that addressed patient populations or individuals that may present particular profiles: individuals exposed to stress, professional athletes, war veterans, children and adults with ADHD, and clinical older patients.
3. Practicing biofeedback may lead to better attention and executive function.

ALTITUDE: The Impact of a 14-Day Altitude Training Camp on Olympic-Level Open-Water Swimmers' Sleep

PRACTICAL TAKEAWAYS -

1. The purpose of the present study was to evaluate possible changes of actigraphy-based and subjective sleep parameters in a group of elite open-water swimmers during a 14-day altitude training camp (ATC) at 1500 m.
2. No significant differences in objective and subjective scores of sleep quality were detected, whereas the sleep onset time and sleep offset time significantly differed among PRE, T1, T2, and T3: elite athletes started to sleep and woke up ≃ 1 h earlier the first two days of ATC compared to PRE.
3. Sleep quality was not negatively influenced by a 14-day altitude training camp at 1500 m in a group of Olympic-level elite swimmers despite an increase in perceived exertion during training sessions.
4. In the Twitter discussion where I shared this, Gabriel Della Mattia share some fascinating data from his athletes.

SLEEP: The impact of daytime napping on athletic performance

PRACTICAL TAKEAWAYS -

1. Prevailing findings indicate that following a normal sleep night or after a night of sleep loss, a mid-day nap may enhance or restore several exercise and cognitive performance aspects, while concomitantly provide benefits on athletes’ perceptual responses.
2. Most, but not all, findings suggest that compared to short-term naps (20–30 min), long-term ones (>35–90 min) appear to provide superior benefits to the athletes.

ALTITUDE: Same Performance Changes after Live High-Train Low in Normobaric vs. Hypobaric Hypoxia

PRACTICAL TAKEAWAYS -

1. Well-trained triathletes were split into two groups and completed two 18-day LTHL camps during which they trained at 1100–1200m and lived at 2250m under NH (hypoxic chamber) or HH (real altitude) conditions.
2. No difference was found in hematological parameters. The 3-km run time was significantly faster in both conditions 21 days after LHTL, and no difference between conditions was found at any time.
3. Increases in VO2max and performance enhancement were similar between NH and HH conditions.

PHYSIOLOGY: Endurance training affects lactate clearance, not lactate production

PRACTICAL TAKEAWAYS -

1. Metabolic clearance of lactate in trained animals was 37% and 107% greater than in controls during easy exercise and hard exercise, respectively.
2. The effect of endurance training is not on production of lactate but on its clearance from the blood.