Who isn’t shattered these days? Between nine hour shifts, trying to maintain some sort of social life, dealing with an endlessly depressing news cycle and fitting exercise into our days, we’re running on red. We’re tired. You might be so tired, in fact, that you end up cancelling pilates classes or run sessions.

If you’ve checked your iron levels and made a genuine attempt to get eight hours’ sleep, then it’s time to start looking at what else might be sapping your energy. And a good place to start is your hormonal cycle.

While fatigue (that deep-boned tiredness that interferes with your plans and work) is something that really does require medical attention, having more mild energy peaks and troughs is actually a sign of good hormonal health.

It was my own Duracell-like capacity for energy that first alerted me to the possibility that I might not be hormonally balanced. A few years ago, I was doing a training programme at a small gym. The PT remarked one day that it was amazing how I never seemed to get tired. I was able to push through brutal workouts five days a week, four weeks a month, with no variation in weight lifting ability, training capacity or rest requirements. I hadn’t told anyone at the time that my periods had mysteriously ground to a halt. 

Today, enjoying normal hormonal health, I’m far more predisposed to energy fluctuations. Some weeks, interval sessions feel easy and I feel strong at the gym; others, I can barely drag my body through a slow 5K. 

All this is as it should be, says leading sports dietitian Renee McGregor. We should feel slightly different every day, and that’s because our hormones affect us differently every single day. “But equally, it’s the lifestyle factors and the hormones together that can infiltrate your energy levels,” she tells Strong Women. “We know there are certain points in the cycle where you’re probably going to feel more tired without a doubt, and especially if you don’t understand what’s going on, your behaviour might enhance that.” 

To put menstruation simply, you’ve got your follicular, luteal and ovulatory phases. It’s in the follicular phase that your oestrogen and progesterone are fairly flatlined. As you get closer to ovulation, follicle-stimulating hormone (FSH) and lutinising hormone (LH) rise and then oestrogen rises. When progesterone becomes dominant in the luteal phase, you might start to notice PMS-type symptoms. “You’ll definitely need to use more carbs for fuel at that point and if you’re not and you’re trying to do too much exercise at that point, you’re going to feel rubbish,” McGregor says.

A lot of women also notice a change in their heart rate at that time, with it rising in the second part of their cycle. If you don’t track your heart rate, you may just notice that the same workout you did two weeks ago now feels much harder. That’s not to say that you need to change anything at any point of your period; McGregor doesn’t agree with telling women how to exercise or eat at any point of their cycle because the science simply doesn’t exist to back that up yet.

My own issues started a few months after coming off the pill, which I’d taken for years and which had controlled my mood and energy levels (again, no dips or rises). McGregor explains that certain contraceptives will downregulate your hormones meaning that you probably won’t get the same ups and downs as other women. For those who are on the combined pill and who take a monthly break, a slight change in mood and energy may be felt but McGregor suggests that it might be partly psychosomatic. “I wonder if that is slightly more placebo because if you’re expecting a bleed, you might expect to feel a bit rubbish,” she says.

If you don’t have periods because they’ve disappeared (ie living with Relative Energy Disorder in Sport (RED-S)), then you might go though dips without actually noticing. McGregor explains that when you’re in RED-S, “everything’s flatlined. You’re not going to see energy disruptions due to hormones but you may still have energy dips due to (lack of) foods”. In my case, I was so disconnected from my body, that I’d push through with training without really clocking if I felt energised or not. 

The hard thing, in my experience, is understanding your energy levels in comparison with men. If you, like me, often work out with a male housemate or partner, then it’s easy to try to compete against them. That, McGregor says, is a pointless task as “men don’t have to work as hard to get the performance outcomes that women do”. 

We have to work significantly harder to get the same performance outcomes because we don’t have testosterone in the same supply as men, she points out. She suggests that, if you do train with a guy, it’s worth getting to know your cycle so you can anticipate the weeks in which you might find your regular workouts more challenging – and talking about that fact with your training partner.

For more hormone-related fitness content, check out the Strong Women Training Club.

Images: Getty