75 Hard Period & Cycle Rules: How to Modify Around Your Hormones
Why 75 Hard rules don’t work without cycle modifications
The original 75 Hard rules — two daily workouts, gallon of water, no rest days — were designed without regard to the menstrual cycle. Following them rigidly through a full cycle frequently triggers:
- Luteal-phase exhaustion (the body needs more sleep, fewer hard workouts)
- Heavy-flow hydration mismatches (more water doesn’t fix iron loss)
- HPA-axis fatigue (cortisol stays elevated without rest)
- Worsened PMS (under-fueling exacerbates symptoms)
The fix is mechanical: match training and intake to cycle phase.
Phase-by-phase 75 Hard adjustments
Menstrual phase (days 1–5)
- Replace the second workout with a 45-minute walk
- Drop water from 1 gallon to 3 L
- Add an electrolyte packet (sodium + potassium + magnesium)
- Eat iron-rich foods: red meat, lentils, spinach, fortified cereal
- Sleep 8+ hours
- Do not skip the photo or reading
Follicular phase (days 6–14)
- Two full 45-minute workouts as written
- 1 gallon of water
- This is when 75 Hard rules work best — biology is on your side
Ovulation (days 12–16)
- Use the energy peak for your hardest workouts
- Hydrate aggressively (1 gallon target stays)
- Be careful with intense outdoor workouts in heat — cycle hormones affect heat tolerance
Luteal phase (days 15–28)
- Reduce intensity on the second daily workout (steady-state cardio over HIIT)
- Keep carb intake up — do not cut
- 8+ hours sleep, non-negotiable
- Magnesium glycinate at night helps PMS-related sleep disruption
What about hormonal birth control?
On combined hormonal birth control, your cycle’s natural luteal-phase demands are blunted. You can typically follow the standard 75 Hard rules more rigidly. Still monitor for over-training symptoms (resting heart rate elevation, sleep disruption, mood changes).
What about pregnancy?
Stop 75 Hard. Switch to Glow Within or pause your challenge entirely with OB clearance to resume after at least 12 months postpartum.
How the Her 75 app handles this
In the Her 75 app’s 75 Day Hard mode, you input your cycle length and start date. The app then suggests modifications each day — without triggering a restart. You can also toggle "strict mode" if you want Frisella’s original rules with no flexibility.
Related guides
Frequently Asked Questions
Will I have to restart 75 Hard if I modify for my period?+
In the Her 75 app's 75 Day Hard mode — no. The app considers cycle-aware modifications a feature, not a violation. In Andy Frisella's original 75 Hard rules, the program does not address this — so technically any deviation is a restart. The Her 75 modification system gives you a sanctioned alternative.
How much water should I drink on my period during 75 Hard?+
Drop from 1 gallon (3.8 L) to 3 L on heavy-flow days (typically days 1–2 of menstruation). Add an electrolyte packet — sodium, potassium, magnesium. The standard gallon target during menstruation has been linked to hyponatremia in case reports.