Menstrual cycle shortest and longest cycle lengths is considered very irregular. The average menstrual cycle lasts 28 days. The variability of menstrual cycle lengths is highest for women under 25 years of age and is lowest, that is, most regular, for ages 25 to 39. Subsequently, the variability increases slightly for women aged 40 to 44. The luteal phase of the menstrual cycle is about the same length in most individuals (mean 14.13 days, standard deviation 1.41 days) whereas the follicular phase tends to show much more variability (log-normally distributed with 95% of individuals having follicular phases between 10.3 and 16.3 days).
Menstrual cycle occur as a result of adopting a restricted diet, as well as engaging in a high amount of exercise. Finally, the cycle is affected more by a vegetarian diet compared to a non-vegetarian diet. Studies investigating effects of the menstrual cycle on alcohol consumption have found mixed evidence. However, some evidence suggests that individuals consume more alcohol during the luteal stage, especially if these individuals are heavy drinkers or have a family history of alcohol abuse. The level of substance abuse increases with PMS, mostly with addictive substances such as nicotine, tobacco and cocaine. One theory behind this suggests this