Does your period change during summer? If you feel like your menstrual cycle is affected by the seasons, you’re not wrong. The vast majority of us will have also experienced huge lifestyle shifts in recent months due to lockdown, resulting in hormone shifts, changes to our cycles, and periods that just might feel a lil outta whack. This is because our cycles and hormones are easily influenced by external factors. Throw in the change of seasons right off the back of lockdown and, well, the stress of being a human in this world right now, it’s likely you’re period is pretty unpredictable at the moment. Learning why these changes happen can not only make us more prepared to deal with our cycles but is the first step to learning how to harness and balance our hormones.
How does summer affect your period?
Our menstrual cycles tend to be shorter in summer. They’re shorter by less than a day, on average, but if you’re feeling the effects of the changes of the seasons on your cycle, you’re not imagining it – there’s actual science to back it up. And the more drastic the weather change, the more likely it is that the effects of this are felt.
In the U.K., we tend to get very sudden, extreme heat waves that seemingly come out of nowhere and then vanish, leaving us fighting the impulse to turn the heating on in August.
Why does the weather affect our periods?
The seasons affect our periods because, during summer, our bodies produce higher quantities of Follicle Stimulating Hormone (FSH), which increases our chances of ovulation and thus shortens our cycles. FSH stimulates the follicles in your ovaries to grow and mature, and eventually release an egg at ovulation.
It’s been found that, in summer, there is a trend towards increased FSH secretion, larger ovarian follicle size, and a higher frequency of ovulation. Menstrual cycles were also found to decrease in length (the first day of your period to the last day before it starts again) by 0.9 days.
The research concluded that it was increased sunshine, rather than temperature, which led to the cycle changes. During summer or in warmer, sunny climates, your body is producing more Vitamin D. Lower levels of vitamin D have been found to contribute to a longer follicular phase and a longer overall menstrual cycle; longer menstrual cycles are more likely to be anovulatory – meaning ovulation didn’t occur. In winter, ovulation occurs and average of 71% of the time. In Summer, this percentage increased to a whopping 97%.
Nature or nurture?
The reason your menstrual cycle changes noticeably during summer (because, let’s be real, that 0.9 day decrease in cycle length isn’t keeping anyone up at night wracked with questions) could have more to do with the changes you’re making in other areas of your life that with the weather itself. Lifestyle factors heavily affect our menstrual cycles and hormone production. One of the key reasons your period changes in summer could well be because you change – your habits, routines, sleep schedule, and even diet. Be honest, in summer you’re probably more likely to spend time outdoors, you’re likely eating much lighter meals than winter’s heavy, warmind dishes, with fresh fruit and seasonal veggies that are significantly different than in colder month.
It’s also worth noting that weight changes can greatly impact your menstrual cycle, so if your seasonal dietary changes affect your weight or you’re actively ‘dieting’ during particular seasons, your menstrual cycle will feel the effects.
The stress hormone, cortisol, affects the hypothalamus, an area in the brain necessary for the regulation of hormones. When disrupted by cortisol, the signals it sends to the ovaries become scrambled like an out of tune radio, delaying or even entirely preventing ovulation from occurring. With mood easily impacted by the presence, or lack thereof, of sulight – as sunlight also influences sertoinin production – it’s not suprising that the knock-on effects of dramatic seasonal changes have big consequences for our cycles.
Understanding and adapting to your cycle changes
While it may not be as simple as ‘summer = shorter periods’, it is clear that summer, both due to the longer, brighter days it brings and the social and personal routine changes it inspires, definitely has an affect on our cycles.
If you’re feeling thrown by the change of season – whether now or in a few months when the shorter, colder days creep back into our lives, you can learn to manage your cycle and harness your hormones through diet, exercise, and wellness practises.