Article
Training Stress Score Overview
Benjamin T. House 1, Andy Galpin 1, Dan Garner 1, Vince Kreipke 1, and Thomas R. Wood 2,3*

What is The Training Stress Score:

Vitality’s Training Stress Score (TSS) provides a window into the likelihood that yourtraining (exercise) load is exceeding your current ability to recover. Such an imbalance cancause problems in several places, including psychological, metabolic, immunologic, in-flammatory, and hormonal markers [1-5]. TSS is a similar concept as “overtraining syn-drome,” where if continued for long enough, can cause detrimental physiological and psy-chological changes [3, 4].

TLDR: A lower value on the TSS suggests the athlete may have entered into a state of over-reaching or overtraining where recovery is being overwhelmed and performance could benegatively impacted (i.e. too much stress for their recovery capacity).

Keywords: Overtraining, Overreaching, Recovery

Experienced Physiological Effects:

  • Fatigue
  • Less regulated mood
  • Sleep disturbances
  • Worsening performance
  • Decreased motivation or desire to exercise

Physiology Deep Dive:

As training stress increases and accumulates, testosterone and the testosterone to cortisol ratio can decrease and even progress into androgen deficiency [6]. Furthermore, sex hormone binding globulin can increase [7, 8], while IGF-1 [8, 9] and prolactin [2] can both decrease significantly. Immune cell number and activity can be also become depressed [10, 11], the risk of infection tends to increase [11-14], and over time chronic inflammation can develop [15]. If left unchecked these maladaptations can lead to chronic decrements in performance over time. Whether an athlete enters a state of functional overreaching (good thing), non-functional overreaching (not good), or overtraining syndrome (bad) depends on whether performance is negatively affected and how long it takes to recover or super compensate once training stress is reduced, recoverability increases, and/or a taper is initiated [3].

Constraint Zones:

These zones breakdown the likelihood that someone’s training load is significantly outpacing their ability to recover, and this maladaptive signal is now being seen in blood-based biomarkers.

Green:

A green on this score means that the athlete’s current training load is unlikely to be beyond their present recovery capacity. A state of overreaching or overtraining is not expected. Proceed with the current training volume and intensity if performance is increasing. If performance is not increasing, training volume and/or intensity may be progressed while supporting adaptation through adequate recovery and nutrition.

Yellow:

Training stress may be higher than the athlete’s current recoverability and the athlete may be entering into a state of overreaching or overtraining. If performance is still increasing or is being maintained, consider assessing other areas such as energy availability or sleep. Aim to increase sleep, add breathwork or meditation to buffer stress, provide adequate macro and micronutrients, and reduce life stressors outside of training. Short-term reductions in training load may be worth experimenting with to see if performance increases.

Red:

Training or life stress is likely overwhelming the body’s current ability to recover and is potentially causing significant changes to underlying physiology. It is possible that the athlete has entered a state of overreaching or overtraining. We recommend objectively assessing performance to see if it has decreased. It is also advisable to assess the low energy availability and sleep signal scores. Prioritize recovery and nutrition, while considering lowering overall training volume until performance is restored or increases beyond baseline.

Author Contributions: Conceptualization, B.T.H, T.R.W.; data curation, B.T.H and T.R.W.; writing—original draft preparation, B.T.H; writing—review and editing, A.G. and T.R.W.; visualization, T.R.W.; supervision, B.T.H and T.R.W.; project administration, B.T.H and T.R.W.; funding acquisition, B.T.H and T.R.W. All authors have read and agreed to the published version of the manuscript.”

Conflicts of Interest: All the authors would like to disclose that they are coaches and writers within the fitness industry. Otherwise, the authors have no conflict of interest to disclose

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