Summary
Physical therapists Dr. Jen and Dr. Dom compare SIT and HIIT training specifically for women in perimenopause and menopause. They define SIT as 20-30 seconds of near-maximum effort with 2-4 minutes rest for 4-6 rounds, versus HIIT with longer work periods at 80-85% intensity and shorter rest. They reference Dr. Stacey Sims's preference for SIT in midlife women. The hosts explore how both protocols affect bone density through mechanical stress and ground impact, fat oxidation, and VO2 max. They argue that HIIT's shorter rest periods and sustained high intensity can raise cortisol in women already dealing with elevated baseline stress from hormonal changes, while SIT's full recovery between efforts provides a "less stress, more gains" approach that better preserves lean mass and stimulates growth hormone.
Key Points
- SIT: 20-30 seconds near-max effort, 2-4 minutes full rest, 4-6 rounds (about 10 min total work)
- HIIT: longer work at 80-85% max, shorter 15-30 second rest periods, 10-30 minutes total
- Both SIT and HIIT stimulate bone formation through mechanical stress, especially with ground impact
- HIIT's shorter rest periods can raise cortisol in women already dealing with elevated baseline stress from hormonal changes
- SIT is viewed as "less stress, more gains" — reduced overall stress while still improving VO2 max, insulin sensitivity, and fat oxidation
- SIT more effectively preserves lean mass and stimulates growth hormone, which declines with age
- Dr. Stacey Sims prefers SIT over HIIT for midlife women due to better hormonal recovery profile
- Start with 1-2 sessions per week of either SIT or HIIT; don't demonize any form of exercise
Key Moments
What SIT training actually looks like
SIT means 20-30 seconds of near-maximum effort (not just sprinting — battle ropes, squat jumps, assault bike, and rower all count) followed by 2-4 minutes of rest, for just 4-6 rounds total.
"Mind you, when we say sprint, it doesn't have to mean that you're literally doing sprints. It's an easy way to think about it, like all out sprints, right? On a treadmill or running somewhere. But it could also be all out battle rope, all out squat jumps, all out..."
Why HIIT can backfire during menopause
HIIT's shorter rest periods and sustained moderate-to-high intensity can raise cortisol in women already dealing with elevated baseline stress from hormonal changes, leading to poor recovery and hormonal disruption.
"Because hit with its shorter rest periods and still working at that moderate to high intensity, it can raise cortisol."
SIT as "less stress, more gains" for midlife women
SIT is described as reducing overall stress while still improving VO2 max, insulin sensitivity, and fat oxidation. It is more effective at preserving lean mass and stimulating growth hormone, which declines with age.
"So it's kind of looked at as like your less stress, more gains type of protocol because it's reducing that overall stress, but while still getting improved VO2 max, it's"
