College Weight Gain Related to Sleep Variability
Studies have confirmed that weight gain among first-year college students is real, even if the so-called “Freshman 15” is an exaggeration. A new study looks into why freshman are susceptible to weight gain. The researchers found that variance in students’ sleep schedules may be to blame. Although many factors could contribute to freshman weight gain, sleep variance, in addition to sleep duration and bedtime, seems to be the key factor. The findings emphasize the need for teaching young adults about healthy sleep habits.
The researchers followed 132 first-semester freshmen at Brown University. The students kept daily sleep diaries, which the researchers later analyzed. After nine weeks, more than half the students had gained nearly six pounds.
The sleep diaries revealed patterns in sleep duration, bedtime, and sleep variance. All of these factors can contribute to weight gain.
On average, the students slept about 7 hours and 15 minutes each night. For optimum health, teenagers should sleep around 9 hours and 15 minutes per night. Other studies have demonstrated that when teenagers are sleep deprived, they are more likely to eat candy or desserts. Short sleep duration could be part of the reason students gain weight.
Late bedtimes are another factor related to weight gain. Students went to bed around 1:30 a.m. on average. Research demonstrates that for each hour later that people go to sleep, there is a 2-point increase in body mass index (BMI).
Sleep variance may be the biggest factor in student weight gain. The researchers found that students have a large variance in their sleep and wake times from day to day. Boys had an especially large variance in sleep, with their sleep and wake times varying by an average of 2 hours and 37 minutes daily—the equivalent of being jet lagged every day. When the body changes schedule, the metabolism attempts to adjust. When the schedule changes from day to day, the metabolic changes can lead to weight gain.
The researchers note that the findings demonstrate a correlation, not a causal relationship. More information is needed about students’ habits to understand why they gain weight in college.
The authors suggest that parents teach their children about sleep needs so they can learn to set schedules when they begin living independently.
This research is published in the journal Behavioral Sleep Medicine.