Why does travelling affect your cycle?

Travelling can directly influence your hormones and the menstrual cycle due to its associations with the circadian rhythm – the body’s “inner clock” (1, 2). This inner clock is responsible for your sleep/wake cycle and repeats roughly every 24 hours (3). When you travel across time zones and get exposed to light at different times, it throws off this clock which is directly involved in the hormonal balance that dictates the menstrual cycle (4). You can think of the circadian rhythm and menstrual cycle as two spinning ends, if one side gets out of balance, it will shift the other. Jet lag also leads to travel-induced stress and other sudden lifestyle changes, which, unsurprisingly, also affect your period. 

What type of travel is likely to affect my menstrual cycle?

It is unlikely that a day trip or long car ride will affect your menstrual cycle, although studies testing lengths and modes of travel and the menstrual cycle are limited. Generally, it is considered relevant when we discuss travel that might impact your sleep cycle, so the more likely culprit would be if you travel on a plane through time zones (4). Unfortunately, it is not just travel that might result in some serious schedule changes. Shift workers are particularly at risk of these effects, with studies reporting that nurses (5), flight attendants (6) and industrial workers (7) who work night shifts have a greater prevalence of menstrual irregularities. 

What if you are on birth control? 

If you are on birth control, travel shouldn’t affect your menstrual cycle. That is unless you forget to bring or take your birth control! Be conscious of changes in time zones when taking your birth control pills, particularly if you are taking a pill with a narrow window like progestin. 

Here are some tips to help manage your cycle when travelling: 

• Consider packing emergency period supplies. No one likes to be caught off guard with a surprise period, which could be more likely due to the impacts of time zone changes on the regularity of the cycle. 
• As much as possible, try to maintain some of your regular routines. Staying active, drinking enough water, and prioritizing sleep, are some great ways to maintain some consistency. 
• Relax. Stress can cause further delays and increase the pain associated with periods (ouch!). So, even though you are on the go, it is still important to check in with yourself and engage in some much-needed self-care. 
• Accept that you can’t avoid all menstrual changes and take the time to settle in. Depending on your travel, stress and jet lag might be unavoidable. Recognise that it might take a few cycles to re-sync or normalise with your regular cycle. 

Bottom line:

It is normal and expected for travel to impact the menstrual cycle. This generally occurs due to shifts in your sleep/wake cycle and from stress on your body (whether that be from anxieties about missing flights, changes in diet changes or even excitement). Prioritize making the effort to check in with yourself and make time for sleep and relaxation. If you are not sure what might be throwing your period off though, it's best to speak with a doctor.