There is a growing body of information out there about training around the menstrual cycle. Particularly, concerning the high and low hormone phase and the types of exercise that might be better aligned with our physiology during these phases. Something we are seeing more and more is the headline “focus on endurance during the luteal phase”. But why might be this be, and what does this mean for climbers?

Where has this come from?

During the luteal phase both estrogen and progesterone are high. This has an effect on substrate metabolism. This means the source of fuel we burn in order to produce energy in the form of ATP changes. When hormones are high, our cells conserve glycogen and burn fats more readily during exercise. This a state that has been termed “glycogen sparing”. We burn fats more readily during exercise and they are used in the aerobic energy system. This has led to the theory that performance in endurance exercise may be enhanced during the luteal phase. **Although the change in substrate metabolism has been shown, there is no conclusive evidence of its effect on performance.**

What does this mean for climbers?

The first thing to consider is given that fats can only be used in the aerobic energy system. So how much are we relying on this energy system when we climb? The aerobic system is a relatively slow system when it comes to producing ATP. So when we do high intensity exercise we tend to rely on our anaerobic energy systems. Another way to think about this is that exercise done using solely the aerobic system should be sustainable, apart from when glycogen or fat stores become depleted (which would take a long time!), and this is rarely the case when we climb.

Key take away points:

So when it comes to training around the menstrual cycle, what are the take away points for the luteal phase? For route climbers with a focus on endurance training, this may be a good time to focus lower intensity endurance sessions. BUT for strength, anaerobic, or aerobic power training the key take away from this theory is to fuel well with carbohydrates before sessions to help with glucose availability for anaerobic respiration.

Read more articles from our Female Climber Series over at the Lattice Training Blog.