Daytime Sleepiness Linked to Weight Gain Differently by Gender

A recent investigation, published in Sleep Health, sheds light on the nuanced relationship between daytime sleepiness and body weight, drawing attention to important gender differences.

The findings reveal that men grappling with increased daytime drowsiness tend to accumulate a higher body mass index (BMI) over time, while women experiencing similar fatigue appear to gain weight more rapidly, particularly among the younger demographic.

Obesity and Sleep Disturbances

Obesity has emerged as a pressing public health concern, significantly raising the risk of chronic illnesses and premature mortality.

Frequently, sleep disturbances, especially daytime sleepiness, are associated with obesity.

Although many studies have focused on how obesity contributes to sleep disorders—often through mechanisms such as sleep apnea—research exploring whether daytime sleepiness might actually trigger weight gain has been noticeably scant. This study sets out to bridge that gap, investigating how the intensity and fluctuations of daytime sleepiness can influence BMI trajectories over time.

The researchers were keen to uncover gender-specific trends, as earlier studies have hinted that the dynamics between obesity and sleep-related variables can diverge between men and women.

By leveraging longitudinal data along with objective measures of sleepiness, the research endeavors to enrich the understanding of the potential cyclical dance between sleep health and weight control.

Methodology and Findings

The data came from the Wisconsin Sleep Cohort Study, launched in 1988, which has tracked a randomized sample of state employees aged 30 to 60 over the years.

Over the course of two decades, participants underwent regular sleep assessments approximately every four years, resulting in a rich database featuring 2,614 observations from 827 participants. To quantitatively assess daytime sleepiness, researchers employed the Multiple Sleep Latency Test (MSLT), which gauges how quickly a person falls asleep during structured napping sessions—shorter times reflecting greater sleepiness.

BMI was calculated during each visit based on meticulously recorded height and weight measurements taken by trained professionals.

The analysis also considered variables such as age, physical activity, stimulant use, and depressive symptoms. Findings revealed strikingly different patterns linking daytime sleepiness and BMI between the sexes.

In men, a consistent association emerged; as daytime sleepiness increased, so did BMI levels throughout the study period.

This suggests that men who endure chronic daytime sleepiness usually maintain higher BMI levels than their less drowsy counterparts.

However, changes in daytime sleepiness seemed to exert little influence on the personal weight fluctuations among men, implying that while overall BMI is affected, individual weight changes are minimal. For women, the connection between daytime sleepiness and body weight was more intricate.

Initially, higher levels of sleepiness did not strongly correlate with BMI.

Yet, increases in daytime sleepiness over time were tied to more significant weight gain, particularly among younger women.

This observation hints that age might shape the correlation between drowsiness and weight gain, potentially due to hormonal shifts or variations in activity levels.

Implications and Future Research

The researchers speculated on several pathways through which daytime sleepiness might foster weight gain.

Reduced energy could lead people to become less active, while the tendency to crave higher-calorie foods during episodes of sleepiness could contribute to weight issues.

Furthermore, chronic sleep deprivation or ongoing drowsiness might disrupt vital metabolic processes, including insulin sensitivity and energy regulation. Interestingly, the study did not identify sleep apnea—the common culprit behind daytime sleepiness—as a primary driver of the relationships observed.

Although sleep apnea is well-established in its connections with both sleepiness and obesity, this research indicates that the interaction between daytime drowsiness and BMI may operate independently of sleep apnea severity, suggesting a broader influence of sleepiness on weight management. While this study presents valuable insights into the interplay between sleepiness and weight changes, it also acknowledges its limitations.

Although daytime sleepiness and BMI were measured objectively, variables such as physical activity and dietary patterns relied on self-reported data, which could introduce bias.

Additionally, the predominance of white, middle-aged participants may limit the broader applicability of the findings to more diverse populations. Conducted by a team of researchers including Yin Liu, Jodi H. Barnet, Erika W. Hagen, Paul E. Peppard, Emmanuel Mignot, and Eric N. Reither, this study titled “Objectively measured daytime sleepiness predicts weight change among adults: Findings from the Wisconsin Sleep Cohort Study” opens a new avenue for understanding how sleep health may influence weight management in ways that deserve further exploration.

Study Details:

• Title: Objectively measured daytime sleepiness predicts weight change among adults: Findings from the Wisconsin Sleep Cohort Study
• Authors: Yin Liu, Jodi H. Barnet, Erika W. Hagen, Paul E. Peppard, Emmanuel Mignot, Eric N. Reither
• Journal: Sleep Health
• Publication Date: March 2024
• DOI: 10.1016/j.sleh.2024.03.002