What are the best days in my cycle to lift heavy and break PRs?

(Hint: it's not just about motivation—it's hormonal)

Ever had a session where the bar flies up like it’s nothing... Then, two weeks later, the same lift feels like a mountain? It’s not “all in your head”—it’s your hormones.

Let’s break down the most strategic time in your cycle to go after PBs, heavy sets, or max-out days—so you’re not working against your body, but with it.

Your strongest window: the late Follicular → Ovulatory phase

In a typical 28 - 32 day cycle, your power peak usually happens around days 9 - 14.

This is when oestrogen is high, and oestrogen is a powerful performance enhancer.

Here’s why this is the sweet spot for lifting heavy:

• Oestrogen boosts strength and coordination

  • It enhances neuromuscular efficiency (aka better mind-muscle connection), increases collagen synthesis (better joint integrity), and helps with muscle recovery.

• You’ve got more energy + motivation

  • With testosterone also rising near ovulation, many women feel more drive, confidence, and readiness to take on a challenge - whether that’s adding 5kg to your squat or finally hitting that pull-up.

• You're naturally primed for intensity

  • Reaction time, hand-eye coordination, and anaerobic performance all tend to be sharper in this window.

Best days to schedule a heavy lift or test a PR:

• Day 10 - 14 of your cycle (give or take, depending on when you ovulate*)

• If you track ovulation: 2-3 days before and the day of ovulation are your sweet spot

• If you don’t track: mid-cycle is your best guess - roughly 2 weeks after your period starts

*not everyone ovulates on Day 14. If your cycle is shorter or longer, shift this “PR window” accordingly.

A quick note on recovery -

This high-performance window doesn’t mean overdoing it.

Yes, you can lift heavier and go harder, but recovery still matters.

• Prioritise sleep, food, and hydration.

• Refuel with enough protein + carbs post-lift.

• Don’t stack every workout as a max-out day, use this time for testing or progressing.

What about the rest of the cycle?

• Menstrual phase (Day 1-5): You can lift, especially once bleeding eases. Energy might be lower, so stick to moderate loads and listen to your body.

• Early Follicular (Day 6-9): Strength starts climbing. Great time to reintroduce progressive loading and start prepping for heavier work.

• Luteal phase (Day 15-28): Progesterone rises, oestrogen falls. You may feel bloated, tired, or flat. Focus on form, volume, or maintenance, not PBs.

  • Lifting heavy in the luteal phase isn’t off-limits, but your CNS (central nervous system) is more sensitive to fatigue, so don’t force PRs here.

Bottom line?

Your cycle has built-in power windows. And the late Follicular to Ovulatory phase is your best bet for going heavy, fast, and strong.

Start paying attention to how you feel around mid-cycle. If the bar feels light, your body’s telling you something: This is your time to go for it.