We often think of pitching as a technical, biomechanical skill. But beneath the mechanics lies a physiological engine — one that responds to both the physical and psychological demands of competition. A new study of professional pitchers provides the clearest picture yet of in-game heart rate responses, showing that pitching consistently pushes athletes to ~85% of their maximum heart rate. What this means for training, recovery, and performance is more nuanced than simply calling pitching an anaerobic task.

What the Study Found
Researchers monitored 16 professional Single-A starting pitchers across a full season, collecting in-game heart rate data from 682 innings (381 at home, 301 away). Using wireless sensors, each pitcher’s heart rate was normalized to their age-predicted maximum to express intensity as %HRmax.

Key findings included:

• The average in-game intensity was 84.8% HRmax, confirming pitching is an anaerobic, high-intensity task.
  
  
• During home starts, pitchers’ heart rates were significantly higher in the 1st (87.3%) and 2nd (85.0%) innings than in later innings.
  
  
• In the first inning, HR was higher at home than on the road (87.3% vs. 85.8%).
  
  
• Away games showed no inning-to-inning differences, suggesting the psychological arousal of pitching at home may amplify physiological load.
  
  
• Importantly, these values were far higher than previous bullpen or simulated game studies, which reported ~62–75% HRmax — highlighting that controlled environments underestimate true competition intensity.
  
  

Why This Matters

‍This study confirms two things: first, pitching is physiologically demanding at a level consistent with anaerobic conditioning. Second, it highlights how the psychological environment of competition — adrenaline, crowd influence, and arousal — directly impacts physiological output, particularly in early innings.

For strength and conditioning coaches, this means training programs cannot rely solely on simulated environments or bullpen data. The demands of live games are higher, both metabolically and psychologically.

How We Apply This at VeloU

‍At VeloU, we view this 85% HRmax threshold as a diagnostic and developmental anchor point:

• VO₂max testing: Knowing an athlete’s aerobic ceiling allows us to identify the “zones” where they lose control of rhythm, command, or efficiency. This isn’t just about building endurance — it’s about teaching athletes how to regulate heart rate under stress.
  
  
• Targeted conditioning: Our goal isn’t only to survive at ~85%, but to make it harder to even reach that level by training at, slightly above, and just below it. That adaptation shifts the physiological curve, so in-game demands feel more manageable.
  
  
• Psychological overlay: Elevated HR in the first inning — particularly at home — reflects more than mechanics. Hormonal responses like adrenaline and cortisol surge with competition stress, amplifying workload. This means any comprehensive program must prepare pitchers not just physically, but also psychologically, to manage those moments.
  
  

The takeaway is that training should reflect both the measurable physiological intensity of the game and the invisible psychological layers that elevate it further.

Pitching is more than an anaerobic sprint repeated over innings. It’s a physiological and psychological stressor that pushes pitchers to operate near 85% of their maximum capacity, with spikes driven by environment and competition. Understanding VO₂max, targeting the right training zones, and acknowledging the role of mental stress can all help athletes prepare more effectively for the true demands of the mound.

Reference
Cornell, D. J., Paxson, J. L., Caplinger, R. A., Seligman, J. R., Davis, N. A., Flees, R. J., & Ebersole, K. T. (2017). In-game heart rate responses among professional baseball starting pitchers. Journal of Strength and Conditioning Research, 31(1), 24–29.