Changes in serum metal concentrations following high-intensity interval training: A 16-week pilot study
Question
Does a 16-week 4x4 HIIT program change serum metal concentrations in adults with overweight or obesity and metabolic syndrome risk factors?
Summary
In a small uncontrolled pilot study, 16 weeks of treadmill 4x4 HIIT was followed by reductions in several serum metals and hip circumference in inactive adults with excess weight and metabolic risk factors. Because there was no control group, the study is hypothesis-generating rather than proof that HIIT caused the metal changes.
Methodology
- Fifteen inactive adults with BMI >25 kg/m2 and metabolic syndrome risk factors completed the pilot.
- 15 participants.
- Treadmill.
- Work intervals: 4 minutes at 90% HRmax.
- Recovery: 3 minutes active recovery at 70% HRmax.
- Intensity: 90% HRmax work intervals.
- 40 minutes.
- 3 sessions/week.
- 16 weeks.
- Longitudinal pre-post pilot study
- Serum metals, Hip circumference, and Cardiometabolic markers were tracked.
Outcomes
Metals
Mercury, lithium, aluminum, manganese, nickel, and lead decreased after HIIT.
Reported p values included Hg p=0.022, Li p=0.002, Al p=0.018, Mn p=0.003, Ni p=0.014, Pb p=0.025; FDR significant, Bonferroni not significant.
Hip circumference
Hip circumference decreased after training.
p=0.001, d=1.04.
Clinical markers
Weight, BMI, waist circumference, blood pressure, and biochemical variables did not significantly change.
Insights
- The 4x4 format can be implemented with HR or RPE adjustment in adults with metabolic risk.
- Unsupervised HIIT sessions should include adherence capture if used in applied programs.
Limitations
- No control group.
- Small sample.
- Unsupervised weekly session adherence could not be ensured.
- Serum metals are surrogate outcomes.
Safety
- The protocol was described as well tolerated; adverse events were not otherwise detailed.