The body needs exercise to stay fit and healthy. If you are not used to exercise it can be a shock to the system, especially if your workouts are too intense. The female body consists of a balance of different hormones, and things such as exercise can have an effect on how hormones regulate the body.
Cortisol, which is produced by the adrenal glands, is a hormone that is directly affected by exercise. One of its functions is to accumulate the body's supply of carbohydrates, whose primary function is to provide energy for the body. When the intensity of your workout is higher, your body's need for carbohydrates is triggered, which in turn produces more cortisol. The amount of cortisol produced by the body can have an effect on your menstrual cycle.
The amount of cortisol produced by the body can also have an effect on your sex hormones. Large amounts of cortisol can have an effect on the normal levels of estrogen and progesterone. This can stop ovulation, meaning that your period does not arrive. It can also change the duration of your period or, if you are mid-cycle, it can cause early spotting. During the female cycle, before an egg becomes fertilized, progesterone will tell your body to release the uterine lining that was built up by estrogen in preparation for a fertilized egg. Your levels of progesterone can decrease early if the body produces too much cortisol. This can lead to an early breakdown of the uterine lining, which is when early spotting may occur.
There are a number of different reasons as to why the body produces excess cortisol. One of the main reasons is stress, but your body can become stressed due to over-exercising, strict dieting, emotional stress or too much alcohol or caffeine. So if you increase the intensity of your workout regimen at the same time as any of the other factors are taking place, you are more likely to experience changes in your menstrual cycle.
If you are new to exercise, you can avoid causing shock to your body by beginning slowly and steadily, increasing the intensity of your workouts as your body becomes used to your new regimen. If you do start to spot, it may not be because of your exercise routine but due to other factors in your life. If you are worried about continuous spotting, consult your doctor.