RESEARCH: studies shared from 24 to 30 Apr 23

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This week's quick summary:

• Mental health disorders in ultra endurance athletes
• Pre-sleep protein increases mitochondrial protein synthesis
• Postprandial glycemic response to exercise before and after meal
• Comparing 2 HIIT programs on rowing performance and VO2kinetics
• Ordered eating and its effects on postprandial health markers

PSYCHOLOGY: Mental health disorders in ultra endurance athletes per ICD-11 classifications

The demands of ultramarathon racing are high and these can result in mental fatigue during an event (which can result in reduced motor control). I've shared studies in the past that provide means of managing the mental fatigue in races (caffeine, odours and music, and external performance feedback). Rather than looking at racing, this study looks at training and how "the mental-health consequences of high-volume training associated with ultra-endurance sports are not well understood".

STUDY DETAILS

1. We conducted a narrative review summarizing primary observations about mental disorders per ICD-11 criteria in ultra-endurance athletes (UEAs) using a keyword search in Scopus and PubMed
2. We identified 25 papers discussing ICD-11-classified psychiatric disorders such as depression, anxiety, eating disorders (ED), attention-deficit/hyperactivity disorder, and schizophrenia in ultra-endurance athletes.
3. Of the twenty-five studies reviewed, ED is evident in fifteen, depression in nine, anxiety in five, alcohol use in two, psychosis in one and ADHD in one.
4. Based on our assessment, we advocate for future research that examines the UEA population, including recreational and elite athletes.
5. Per our review, the onset of mental disorder is not well understood, and it is unknown whether UEAs are motivated to participate in UESs for amelioration of existing symptoms or whether mental disorders develop from chronic high-volume training.

PRACTICAL TAKEAWAY

This paper shows that ultramarathon runners may have certain mental disorders. Whether this is caused by high training loads is unclear; and, whether or not it greater than observations in the normal population is also unclear. However, as an example, previous research I've shared suggested that ultramarathon runners were more likely to have episodes of binge eating (disordered eating) compared to shorter distance athletes. My recommendation is to be aware of these different disorders so they can be identified in endurance athletes.

NUTRITION: Pre-sleep protein ingestion increases mitochondrial protein synthesis rates during overnight recovery from endurance exercise

Pre-sleep protein has shown to stimulate whole-body protein synthesis rates overnight in young and elderly men and has shown increases in muscle strength after resistance training. This study set out to compare "the impact of pre-sleep whey versus casein ingestion on overnight muscle protein synthesis rates".

STUDY DETAILS

1. Thirty-six healthy young men performed a single bout of endurance-type exercise in the evening (19:45 h).
2. Thirty minutes prior to sleep (23:30 h), participants ingested 45 g of casein protein, 45 g of whey protein, or a non-caloric placebo.
3. Continuous intravenous L-[ring-13C6]-phenylalanine infusions were applied, with blood and muscle tissue samples being collected to assess overnight mitochondrial and myofibrillar protein synthesis rates.
4. Pooled protein ingestion resulted in greater mitochondrial and myofibrillar protein synthesis rates when compared with placebo.
5. Casein and whey protein ingestion did not differ in their capacity to stimulate mitochondrial and myofibrillar protein synthesis rates.
6. Protein ingestion prior to sleep increases both mitochondrial and myofibrillar protein synthesis rates during overnight recovery from exercise.

PRACTICAL TAKEAWAY

Pre-sleep protein ingestion is beneficial for mitochondrial and protein synthesis and it does not appear to matter whether this is whey or casein protein. In professional cyclists during a training camp there did not appear to be a benefit from protein supplementation as they were already consuming sufficient protein. Therefore, my recommendation would be to consume pre-sleep protein in periods of calorie deficit (this could be during periods of weight loss or restricted eating). I would suggest using a 45g dose 30 minutes prior to bed of either whey or casein.

PHYSIOLOGY: Acute postprandial glycemic response to exercise before and after meal ingestion

Previous research has shown that slow postmeal walking reduces postprandial glycemia in middle-aged women. This study "aimed to identify the impact of pre- and post-meal exercise on postprandial glucose excursions" which can help to guide the best time to walk in relation to a meal.

STUDY DETAILS

1. Eight randomized controlled trials (crossover trials, high risk of bias) with 30 interventions in 116 participants (47 diagnosed with type 2 diabetes, 69 without type 2 diabetes) were eligible.
2. Exercise after meal ingestion (real food or meal replacement drinks) led to a reduction in postprandial glucose excursions compared with exercise before eating and an inactive control condition.
3. Pre-meal exercise did not lead to significantly lower postprandial glucose compared to an inactive control.
4. The time between meal and exercise had a moderating influence on postprandial glucose excursions.
5. Exercise, i.e., walking, has a greater acute beneficial impact on postprandial hyperglycemia when undertaken as soon as possible after a meal rather than after a longer interval or before eating.

PRACTICAL TAKEAWAY

Walking immediately after a meal appears to provide the greatest benefit for glucose excursions. My recommendation would be to walk for 20 minutes after a meal to make the most of this moderating influence on postprandial glucose excursions.

INTERVALS: High-intensity interval training, performance, and oxygen uptake kinetics in highly trained traditional rowers

I have shared many studies on intervals (seach for "intervals" on my resources page) as they are a fundamental component of endurance training. I don't believe that there is a single optimal interval training protocol which is why I think it's useful to share and test many different options to see what works best for each athlete. This study provides some insight into different training options as it "compared the effects of 2 high-intensity interval-training (HIIT) programs on traditional rowing performance and VO2kinetics".

STUDY DETAILS

1. Twelve highly trained rowers performed one of two 6-week HIIT protocols: either 3-minute repetitions at 90% (HIIT90; n = 5) of peak aerobic power (PAP) or 90-second repetitions at 100% (HIIT100; n = 7) of PAP.
2. Before (PRE) and after (POST) the training intervention, they performed an incremental test to exhaustion to determine the individual lactate threshold, onset of blood lactate accumulation and PAP, and two 6-minute rest-to-exercise transitions to determine VO2kinetics.
3. No significant changes were observed for rowing ergometer power output at individual lactate threshold, onset of blood lactate accumulation, or PAP or for any parameters of VO2kinetics.
4. No differences were observed between HIIT interventions.
5. The HIIT interventions did not induce significant performance or VO2kinetics improvements, although mean power output at individual lactate threshold, onset of blood lactate accumulation, and PAP increased by 5.7%, 5.0%, and 4.5%, respectively.
6. This suggests that the exact intensity and duration of HIIT sessions performed in the same intensity domain may be of lesser importance than other well-established influential factors (eg, training volume progression, training intensity distribution, altitude training) to develop aerobic qualities in endurance athletes.

PRACTICAL TAKEAWAY

The outcome of this study is particularly useful as it suggests that trying to find the perfect interval training session or protocol is not that important in developing the aerobic qualities of athletes. Rather, ensuring that there is interval training included in a well-designed training plan is sufficient. My recommendation would be to find the types of interval training sessions that athletes enjoy and that can be implemented into a plan consistently. Then use these intervals appropriately and without seeking out "better" options or different protocols unless there is a specific reason to do so.

NUTRITION: Ordered eating and its effects on various postprandial health markers

This study is on a concept that I have not seen much research on: the impact of the order in which macronutrients are eaten during a meal. The authors "aimed to systematically evaluate evidence from acute experiments that modified the order in which foods were consumed in isocaloric meals".

STUDY DETAILS

1. The review included acute interventions that administered isocaloric meals of the same foods but with foods eaten in different orders.
2. All reports that assessed glucose and insulin showed a tendency toward lower levels, at least over parts of the PP period, by consuming carbohydrates last.
3. GLP-1 tended to be higher in carbohydrate-last conditions, though this was only measured in a few studies.
4. Perceptual responses (hunger, fullness, etc.) were not consistently different between conditions in two studies.
5. Findings indicate that, at least acutely, there may be benefits to eating carbohydrate after vegetable and/or protein-rich foods.
6. The most consistent effect (judged as moderate certainty) is that carbohydrate-last meal orders tend to lower blood glucose and insulin excursions.

PRACTICAL TAKEAWAY

It appears that eating carbohydrates last during a meal has benefits for blood glucose and insulin excursions. If it's possible, eating carbohydrates last, and perhaps taking a walk after eating (see the study above) may be the best way to optimize health around meal times.