Should women plan training around the phase of the menstrual cycle?

Bryan JohnsonNo clinical or scientific credential claimed · technology founder and quantified-self subject

Yes. Train hard in the follicular phase, back off in the luteal phase, and raise protein when you do

What it rests onA hormonal mechanism argument: rising estrogen in the follicular phase improves insulin sensitivity, muscle synthesis and recovery and keeps core temperature lower, so intensity lands better; rising progesterone in the luteal phase raises core temperature, reduces insulin sensitivity and slows recovery, so zone 2 and lighter strength work with protein raised from 1.5 to 2.0 g per kg. The luteal-phase supplement list maps onto products he sells.

Stacy T. SimsPhD · exercise physiologist and nutrition scientist

No longer. Decide today's session on readiness, not on the calendar. Cycle awareness stays; cycle prescription goes

What it rests onA dated first-person revision of her own position by the researcher who popularised it: 'I was one of the first to start talking about this, about 7-8 years ago', and 'the more data we collect, the clearer it becomes: there's no single right way for all women to train around their cycles'. Her replacement is 'Train by readiness, not the calendar. If energy, sleep, and HRV look good, great, go for it. If not, modify intensity or focus on technique and recovery.' She keeps the awareness explicitly: 'Cycle awareness is still powerful; it's part of understanding your physiology. But it should guide you, not confine you.'