PMID 41323564

Research
All papers

Effects of heat stimulation after high-intensity interval training on serum adipokines, eHSP72, and immunoglobulins in men with obesity

Kim DH, Kim ES, Lee JS, Yoon SJ

Question

What are the effects of heat stimulation after HIIT on adipokines, eHSP72, and immunoglobulins in men with obesity?

Summary

In 48 men with obesity, 12 weeks of HIIT followed by heat stimulation, MICT followed by heat stimulation, or heat stimulation alone improved adipokine markers. The HIIT plus heat group and MICT plus heat group improved body weight, BMI, and body fat percentage, and HIIT plus heat showed the largest eHSP72 response.

Methodology

  • Adult men with obesity aged 20-40 years
  • 48 participants.
  • Cycle ergometer HIIT and hot water immersion.
  • Work intervals: 4 minutes.
  • Recovery: 3 minutes active recovery.
  • Intensity: 85-95% HRmax for work bouts; 70% HRmax recovery; 40 C hot water immersion.
  • About 33 minutes exercise block plus stretching and 20 minutes heat stimulation.
  • 3 sessions/week.
  • 12 weeks.
  • Randomized three-arm controlled intervention
  • Body composition, Adipokines, eHSP72, and Immunoglobulins were tracked.

Outcomes

Body composition

HIITHS and MICTHS improved body weight, BMI, and body fat percentage.

Improved

Adipokines

Adiponectin increased and leptin decreased in all groups.

Improved

eHSP72

eHSP72 increased, with the greatest response in HIITHS.

Improved

Immunoglobulins

IgA and IgG increased; IgE decreased in HIITHS and HS.

Mixed

Insights

  • Post-exercise heat is a distinct intervention and should not be bundled into ordinary HIIT recommendations.
  • Heat exposure after HIIT requires screening and clear dosing.

Limitations

  • No HIIT-only group
  • Male-only obesity sample
  • Biomarker-focused outcomes

Safety

  • No adverse events, heat-related complications, or safety concerns were observed during the 12-week intervention.
  • All 48 participants completed the protocol without missed sessions or early terminations related to heat intolerance.
  • No participants reported dizziness, nausea, vomiting, excessive fatigue, headache, palpitations, chest discomfort, shortness of breath, muscle cramps, or faintness.
  • Post-heat temperatures remained within normal physiological limits, and no sessions required early termination or temperature-management interventions; 20 minutes hot water immersion at 40 C was reported as well tolerated and safe in men with obesity.