No Evidence for the Efficacy of Slow-Paced Breathing as a Recovery Strategy After Sprint Interval Training

Breathing practices are increasingly adopted by athletes due to the potential benefits for recovery, performance, and well-being. Slow-paced breathing is believed to increase cardiac vagal activity and relaxation, potentially supporting adaptive processes. Sprint interval training, by contrast, elicits a strong stress response. Therefore, we hypothesized that adding slow-paced breathing to highly demanding sprint interval training would enhance recovery, as indicated by cardiac autonomic control and sleep metrics, ultimately contributing to greater performance gains.

Thirty-four participants were randomized into an intervention or control group. While both groups completed 4 weeks of supervised sprint interval training, only the intervention group practiced slow-paced breathing after each training and every evening before bedtime. Running performance, vagally mediated heart-rate variability (root mean square of successive differences), and sleep metrics were assessed throughout the intervention to evaluate the potential benefits of the breathing exercise.

Sprint interval training led to significant improvements in maximal power decrements (-8.26%, 95% CI, -11.48 to -5.04, P < .001) and overall work (8.84 kJ/kg, 95% CI, 4.58 to 13.1, P < .001), but performance gains did not differ between groups (P > .05). Unexpectedly, nocturnal heart rate showed a slight increase over time in the intervention group (+3.1 beats·min-1, 95% CI, 0.47 to 5.72, P < .05) compared with the control group.

Despite positive effects reported in other training and performance contexts, 4 weeks of daily slow-paced breathing did not confer additional performance improvements or physiological benefits when combined with sprint interval training. These findings suggest that 10-minute sessions of slow-paced breathing following highly demanding sprint interval training offer limited value for enhancing performance or supporting recovery.