The reason for feeling tired during your period is primarily due to hormonal fluctuations, especially the drop in estrogen and progesterone levels, which affects energy and mood. Additionally, period fatigue can be caused by factors like iron deficiency from blood loss, disturbed sleep due to cramps or discomfort, and the physical energy demands of menstruation itself.

Hormonal Changes

During the second half of the menstrual cycle (the luteal phase) and continuing through menstruation, estrogen and progesterone levels fall significantly. This hormonal decline leads to reduced serotonin and dopamine levels in the brain, resulting in feelings of tiredness, fatigue, and sometimes mood changes like irritability or depression.

Iron Deficiency and Physical Factors

Heavy menstrual bleeding can cause iron deficiency anemia, which reduces the oxygen-carrying capacity of red blood cells and leads to physical fatigue and weakness. Period pains, cramps, and mood disturbances also contribute to sleep disruption, further worsening tiredness.

Energy Demand and Lifestyle

The body expends energy during menstruation for uterine contractions and shedding the uterine lining, which can be exhausting. Stress, unhealthy diet, and insufficient sleep can amplify fatigue during the period. Regular light exercise and proper nutrition may help alleviate some of the tiredness.

In summary, feeling tired during your period is common and multifactorial, with hormonal fluctuations as the central cause, alongside blood loss, sleep disturbances, and the physical demands of menstruation all playing roles.