RESEARCH: Studies from 18 to 24 Mar 24
Sharing research and insights from coaches, scientists and athletes to help us improve endurance performance.
This week’s quick summary:
Lifelong endurance exercise and age-related VO2 Max decline
Competition nutrition practices of elite ultramarathon runners
Effects of a 16-day moderate altitude training camp
Improving the diagnosis of overreaching and overtraining
Ketone ingestion increases post-exercise serum erythropoietin
PHYSIOLOGY: Lifelong endurance exercise as a countermeasure against age-related decline: Physiological overview and insights from masters athletes
The studies I’ve shared on VO2 Max focus on the link between performance and VO2 Max (see the PHYSIOLOGY - VO2 Max archive). However, as athletes age, their VO2 Max declines and performance declines along with it. In this overview, the authors “explored the impact of lifelong endurance exercise on age-related decline in maximum oxygen consumption”.
OVERVIEW DETAILS
Evidence from masters athletes supports lifelong endurance exercise in slowing VO2 Max decline.
Examples, such as a centenarian cyclist with a VO2 Max of 35ml/kg/min, highlight high values across ages.
Lifelong exercise may lead to a linear decrease in VO2 Max, maintaining higher levels than the general population.
Physiological changes with inactive aging, including reduced cardiovascular function and muscle capacity, negatively impact VO2 Max.
Lifelong exercise can mitigate many of these changes, though maximum heart rate decline may persist.
PRACTICAL TAKEAWAY
The authors of this overview recommend that regular, lifelong endurance exercise can mitigate age-related declines in maximum oxygen consumption, potentially enhancing overall health and longevity. My takeaway is to continue “training for life” to hold on to the hard-earned physiological adaptations athletes have made over their lives and to be able to continue enjoying their sports.
NUTRITION: Competition nutrition practices of elite ultramarathon runners
I think it’s valuable to look at elite athletes and athletes partaking in specific events to learn examples of best practices. I’ve shared studies on the periodisation of nutrition during a Grant Tour, dietary observations of 24hr runners, and fluctuations of fluid and nutrition intake during a 24hr event. In this paper, the authors set out “to characterize the specific fueling strategies undertaken by elite ultramarathon runners”.
STUDY DETAILS
Three veteran male ultrarunners participated, with an average age of 35 years and a 16.7-hour best time for a 100-mile race.
Athletes completed a competition-specific nutrition intake questionnaire for 100-mile races, reporting an average prerace breakfast comprising 70g CHO, 29g protein, and 21g fat.
During races, athletes consumed an average of 1,162g of CHO (71g/hr), with minimal fat and protein intake, totaling 5,530 kcals (333 kcals/hr), with 93% from commercial products.
Additionally, athletes reported consuming 912mg of caffeine and 6.9g of sodium during races.
Despite limited professional nutritional input, athletes adopted fueling strategies maximizing CHO intake, aligning with evidence-based recommendations.
PRACTICAL TAKEAWAY
This study showed that elite ultramarathoners prioritise carbohydrate intake during races, consuming approximately 71g per hour alongside caffeine and sodium supplementation. This paper was from 2016 and there are athletes trying to ingest more carbohydrates now, but I think this is a very impressive rate of ingestion for over 16 hours of competition. My takeaway from this study is that it is possible to consume high levels of carbohydrates for the duration of an ultramarathon. I recommend that athletes test these levels of nutrition intake and aim to include gut-training protocols into their long runs if they struggle to adhere to recommended nutrition guidelines for performance.
ALTITUDE: Effect of a 16-day altitude training camp on 3,000m steeplechase running energetics and biomechanics
Based on the studies I’ve shared on using altitude to improve performance (see my archives on ALTITUDE), my recommendation for athletes is to spend at least two weeks and up to four weeks at 2000m to 2500m for optimal adaption. However, the logistics and ability to do this can be limited and athletes may still benefit from lower altitudes. In this study, the authors set out “to assess the impact of a 16-day altitude training camp [at 1600m] on the energetics and biomechanics of an elite female 3,000m steeplechase runner”.
STUDY DETAILS
A 16-day intervention involved living and training at 1,600m altitude.
Maximal oxygen uptake (VO2max) was determined through a maximal incremental test at sea level.
Before and after the intervention, the participant completed a training session consisting of 10 × 400m with 5 hurdles, with measurements including oxygen uptake, blood lactate, stride length, stride rate, and biomechanical parameters.
Mean oxygen uptake during the trials remained consistent, representing 84–86% of VO2 Max, with no significant change pre- to post-intervention.
Biomechanical analysis showed increased running velocity and stride length post-intervention, along with improvements in hurdle take-off and landing velocities and maximal hurdle height.
PRACTICAL TAKEAWAY
This study showed the benefits of a 16-day altitude training camp for an elite female steeplechase runner. Interestingly, her aerobic metabolism remained unchanged, yet the glycolytic metabolism improved, leading to enhanced running velocity and biomechanical efficiency. At higher altitudes, athletes often have to reduce their speed in training to account for the altitude. The theory of training at altitude is that the athletes’ physiology can be improved from the altitude stimulus and employing specific training sessions at lower altitudes can maintain the ability to race at high speeds. This study suggests that a lower altitude may offer velocity benefits but the athlete saw no aerobic benefits.
As this is a case study of a single athlete who saw no aerobic benefit from her time at altitude, I continue to recommend the altitude training protocols that I mentioned in the introduction. For athletes competing in events where velocity is critical, they can follow a live-high-train-low protocol or descend to lower altitudes during the altitude training camp for specific sessions.
PHYSIOLOGY: Improving the diagnosis of nonfunctional overreaching and overtraining syndrome
Athletes are often willing to perform a period of overload training to try and improve performance. However, if the athletes go into a period of a functional overreaching prior to a taper they may not see benefits, and other research suggests that there does not seem to be evidence to suggest that FOR is necessary to induce performance improvements. There is also a dangerous potential of overreaching extending into overtraining which can have long-term negative impacts of that can have on training and performance. In this study, the authors set out “to simplify and optimize the distinction between nonfunctional overreaching (NFO) and the “overtraining syndrome” (OTS)”.
STUDY DETAILS
Sensitivity of established cutoff values for hormonal changes was reassessed on a larger sample (n = 100).
Adrenocorticotrophic hormone (ACTH) and prolactin (PRL) responses to the second exercise test emerged as the most sensitive indicators for NFO and OTS.
Cutoff values (NFO > 200% > OTS) showed 67% sensitivity for ACTH and 93% for PRL in OTS cases, and 74% for both in NFO cases.
Discriminant analysis incorporating TOP test measures achieved 98% sensitivity in diagnosing NFO and OTS.
Key discriminating variables included ACTH and PRL responses to both exercise tests and feelings of fatigue.
PRACTICAL TAKEAWAY
This study is technical and the results are not necessarily applicable by athletes and coaches. However, the good news is that clinicians can integrate hormonal and psychological responses from the TOP test to enhance the accuracy of diagnosing NFO and OTS. My recommendation for athletes who are concerned that they may be suffering from OTS is to seek out clinicians who have extensive knowledge and will perform the thorough testing mentioned in this study to arrive at an accurate diagnosis.
SUPPLEMENT: Ketone monoester ingestion increases post-exercise serum erythropoietin concentrations in healthy men
I have shared many studies on ketones (see SUPPLEMENT - Ketones) and overall, I’m not yet convinced that there is a definitive case that athletes definitely need to use them. There are some interesting use cases and potential for benefit in recovery, but at this time the cost does not appear to be worth the benefit. Nevertheless, I think this is an interesting supplement to continue to follow. In this study, the authors set out “to uncover the impact of ketone monoester ingestion on post-exercise erythropoietin (EPO) concentrations”.
STUDY DETAILS
Nine healthy men participated in two randomized, crossover trials with a one-week washout period.
Participants underwent 1 hour of cycling, followed by ingestion of sucrose and protein immediately after exercise, with subsequent intake at 1, 2, and 3 hours post-exercise.
In the ketone monoester trial, participants also consumed the ketone monoester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate.
Blood samples were collected immediately post-exercise and at regular intervals for 4 hours.
Results showed a significant increase in serum EPO concentrations with ketone monoester ingestion compared to the control trial. Peak EPO levels were notably higher with ketone ingestion.
PRACTICAL TAKEAWAY
The findings suggest that consuming ketone monoesters post-exercise can elevate EPO concentrations, potentially offering an approach to modifying hemoglobin mass. This is a positive result and may suggest an effective use for ketones. However, the cost of the intervention (~$60 for the ketone dose taken in this study) and the uncertainty of how the increase in serum EPO may lead to improved performance means that I do not recommend this for most athletes. Nevertheless, this may be an option for athletes in a period of overload training as there is additional support to suggest ketones can help in those situations (see this study and this study).
Quick summary from last week’s paid newsletter
Paid subscribers receive a newsletter every week and have full access to all newsletters listed in the archives (335 studies and practical takeaways). Last week, the newsletter covered studies on the following topics:
Acute fatigue impacts injury risk profile for runners
Effects of 18% CHO hydrogel on skier performance
The placebo effect of caffeine ingestion on running performance
Coach-athlete relationship and burnout symptoms among young elite athletes
Differences between finisher and non-finisher endurance mountain athletes