Evaluating Biomarkers for Health & Performance

Q&A for Session #1
Sports Nutrition Symposium 4.0
Monday January 17th, 2022 @ 12 pm CST

Shawn M. Arent, PhD, CSCSD, FISSN, FACSM, FNAK

From a basic and applied science standpoint, endocrine, biochemical, and nutritional markers have established utility for examining mechanisms underlying the effects of exercise and diet on health and performance. This presentation will focus on identifying assessment strategies including timing, chosen markers, and application of the results to enhance training and overall health.

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  • Do you look at resting heart rate? - and is there a number that is too low? Would you consider a resting heart rate of 44bpm - 46 bpm in a marathon runner normal and result of training? or a concern at all?
    • Look more at HRV (heart rate variability) instead of resting heart rate. Resting heart rate is useful when looking at upticks. Less concerned with day to day fluctuations look at how rolling averages change over a 3-5 day period. Not as concerned about too low of a heart rate, more worried about dramatic changes.

  • Can you talk more about the association between thyroid and cholesterol levels? This is new to me!
    • Not usually tested together but should be sincethyroid hormone plays important role in liver metabolism and has other metabolic effects. Changes in VLDL, total triglycerides, and circulating LDL have been seen with changes in T3, also can be seen with TSH. Often you see an increase in TSH with hyperlipidemia. Testing should be in conjuction with each other

  • Was vitamin D checked in this study with the males/females soccer players?
    • Yes, vitamin D went down as the season went on. Coincided with wearing more clothes as temperatures decreased outside.

  • The example here refers to a classic season for a sport. How can we compare/contrast to the athlete like runners that participate in their sport all year round?
    • Year round athletes have targeted competitions where they need to be at their best so being able to peak at sustain at that time is critical. Good to look at the numbers during this time and then compare to not peak times to see the fluctuations. Can time research at regular times around their training- knowing values at times when they aren't in training is good so you see the change between those two periods.

  • What is the reason for looking at total testosterone v free testosterone in the soccer players?
    • Total testosterone allowed them to compare data to other studies. Free testosterone looks are at the bioavailability. Free and total testosterone did not always change exactly the same. Looking at the free version (of cortisol as well) is also important and may be the better metric to use in calculations for a testosterone:cortisol ratio if you are tracking this over time.

  • How often do you check Hgb, Hct, Ferritin in your female athletes? When do you start to see supplementation change these markers?
    • About every 28 days. Decline is seen with first 4 weeks of a season. Are able to get levels back up in 4-8 weeks after. May need to consider proactive supplementation instead of reactive.

  • Do the iron values in female athletes correlate with cortisol or other inflammatory markers?
    • Yes, from a performance and training load standpoint there are correlations, when looking at time changes: cortisol levels change with stress. Looking at IL-6 beyond an inflammatory cytokine, it also regulates glucose.

  • Does the fit athlete paradox occur in individual sports athletes as well or is it predominantly and issue with team sport athletes?
    • Team sport you see it more because you are making up for other players. When it's just an individual you can see it too but it depends on how much the individual athletes are being pushed. Also can change year by year, in this study once the coaches were aware of this and changed training patterns for athletes- this went away.

  • With the decrease womens' iron levels at T2, how did that correlate/relate to injury risk?
    • Hard to say, can't quantify injury risk- just injury. There were no season ending injuries in this study. Be careful with termonology of injury risk. Manage physiological responses to minimize injury exposure is something that can be done.

  • Are you measuring biomarkers as part of your pre-season physicals?
    • Yes, when they first reported into pre-season before the other performance tests. Other teams have done it as part of the physicals.

  • The study on OC vs Control and increased FFM among control, was diet same/similar in both groups? how were dietary differences accounted for?
    • Dietary exposure was very similar because the same team was used. Dietary recall is flawed. Instead they use nutritional biomarkers to back up the recall.

  • Did you/do you account for athletes being under-fueled or adequately fueled before getting their labs tested?
    • All labs occur at same time- 18-36 hours after game. This avoids the acute response. Doesn't avoid or account for it because that is part of what the research is looking at- whether different fueling changes biomarkers.

  • How would you recommend managing biomarkers and stress reponses in athletes who have a very low off season or no offseason? What would your recommendations be to prevent overtraining?
    • Tracking through season is so important so you know what you can get out of them during the off season. If you can mitigate injury potential during the season and keep them healthy then their off season will be much more productive since they won't be recovering from an injury the first 1-2 months.

  • What intervention strategies would you recommend to prevent the dramatic iron dropoff in the female athletes? Something like dietary and/or supplementation loading for iron pre-season?
    • Get a baseline level. For some female athletes they should be on an iron supplement year round and then increase at different training points.

  • If you could choose specific time points throughout a season to take and monitor biomarkers what would they be?
    • 3-5 weeks, every 28 days preferentially especially for female athletes to keep in approxiately same phase of menstrual cycle. A day or two after a game will start to give you an indication for recovery capability. Tracking over time you will truly be able to see the changes after game time.

  • How challenging is it to get conversations with S&C, training staff, sports med staff on the biomarker results and the recommendations to make changes to the training program or implementing new strategies to recovery modalities.
    • It is contigent on 1) speaking their language and 2) who is the staff. Some people staff get very territorial- but we need to emphasize that it is in the best interest of the athlete. Depends on your relationship with them. You need to get the message across to the coaches so they understand, they are not trained they same way you are so you need to make them understand what you are trying to accomplish. May need to explain things multiple times and in a few ways. Target the things that will make the biggest difference in the fastest time possible.

  • How many people are involved in helping to monitor biomarkers with athletic teams?
    • In a smaller program, what would be the best way to initiate utilizing biomarkers to help athletic performance? Depends on size of program. If you are an effecient program and are only working with one team you can have 1-2 people. What are your resources. You can also do it just by yourself as well depending on the size, you will need help if woking with a 100+ player football team.