Poor Sleep and Reduced Physical Activity

Introduction

Good sleep and regular physical activity are both widely recognized as cornerstones of good health. While a large body of research has focused on how physical activity (PA) may improve sleep, less is known about the reverse: how sleep characteristics influence subsequent engagement in physical activity. Understanding this direction — sleep → PA — is especially important for older adults, among whom sleep problems and physical inactivity both are common and may contribute to adverse health outcomes.

A recent large-scale cohort study, conducted in Sweden and published in 2025, aimed to fill this gap. The study investigated whether sleep duration, sleep disturbances, and symptoms of sleep-disordered breathing (SDB) at baseline were associated with physical activity and sedentary behavior one year later. Nature

The findings offer important insights into the bidirectional nature of the relationship between sleep and physical activity — with potential implications for public health, aging, and individual lifestyle recommendations.

Methods

Study population

The study included 51,247 Swedish women and men, aged between 55 and 93 years at baseline. Nature
Baseline data on sleep and covariates were collected in 2008; follow-up data on physical activity and sedentary behavior were collected in 2009.
Health status was assessed via registry data (comorbidities based on ICD codes), and additional covariates included demographic and lifestyle factors (e.g., education, employment, smoking, alcohol consumption, BMI, depression history). Nature

Sleep assessment

At baseline, participants self-reported:

Typical sleep duration, categorized as short sleep (< 7 h/night), normal sleep (7–<9 h/night), and long sleep (≥ 9 h/night). Nature
Sleep disturbances, defined as often/mostly/always having at least one of the following in the prior three months: difficulty falling asleep, repeated awakenings, early awakenings, or disturbed sleep.
Symptoms of sleep-disordered breathing (SDB): often/mostly/always experiencing snoring or cessation of breathing during sleep. Nature

Physical activity and sedentary behavior assessment

One year later, participants reported their levels of leisure-time PA and sedentary behavior, including:

Walking or bicycling (daily minutes),
Leisure-time exercise (hours per week),
Time spent in sedentary activities (e.g., reading or watching TV). Nature

From these self-reports, binary outcomes were created, classifying individuals as meeting or not meeting recommended PA levels (consistent with typical public health guidelines).

Statistical analysis

Associations between sleep characteristics and PA / sedentary behavior were estimated using binary logistic regression, with adjustment for multiple potential confounders (age, sex, education, employment, cohabiting status, smoking, alcohol, BMI, comorbidities, depression) in the “fully adjusted” model.
Interactions with sex and age group (< 65 vs ≥ 65) were tested.
Sensitivity analyses were conducted among “apparently healthy” individuals (no comorbidities) and after adjusting for physical activity measured ~12 years earlier (in 1997) to account for earlier PA levels.

Results

Participant characteristics

Short sleep (< 7 h/night) was reported by 32% of participants; long sleep (≥ 9 h/night) by 7%.
43% reported at least one sleep disturbance symptom.
24% reported symptoms of SDB (snoring or breathing cessation).
Regarding PA: about one-third of participants walked or bicycled > 40 min daily; 15% did ≥ 2 h per week of leisure-time exercise.
7.5% reported high sedentary activity (> 4 h/day reading or watching TV).

Associations between sleep and next-year PA / sedentary behavior

In fully adjusted models:

Long sleep duration (≥ 9 h/night), sleep disturbance, and SDB symptoms were associated with lower odds of walking/bicycling and leisure-time exercise the following year. Nature
Short sleep duration (< 7 h/night) initially showed lower odds of walking/bicycling and exercise (in models adjusted only for age, sex, education); but after full adjustment, these associations became non-statistically significant.
On the other hand, short sleep, sleep disturbance, and SDB symptoms were linked to higher odds of sedentary behavior (reading or watching TV > 4 h/day).

Effect modification by sex and age

There was a significant sex interaction: the inverse association between sleep disturbance and walking/cycling was somewhat stronger in women, while the negative association between SDB symptoms and walking/cycling was more pronounced in men.
There was a significant age interaction for SDB symptoms and exercise: the negative association was present in middle-aged participants (< 65 years) but not in older participants (≥ 65 years).
For short sleep and sedentary behavior, the positive association was stronger in middle-aged compared with older individuals.

Sensitivity analyses

Among participants without comorbidities, similar associations were observed — though the association between sleep disturbance and exercise was attenuated.
In analyses adjusting for PA levels measured ~12 years prior (1997), results remained largely consistent, although some associations (e.g., SDB symptoms and exercise) weakened.

Interpretation & Discussion

The study provides robust evidence that poor sleep — whether in the form of long sleep duration, sleep disturbances, or symptoms of SDB — may lead to reduced engagement in physical activity and increased sedentary behavior in older adults.

This is important for several reasons:

Bidirectionality of sleep–PA relationship
- While prior research has largely explored how physical activity influences sleep, this study emphasizes the reverse — that sleep affects subsequent activity.
- Given that both sleep problems and physical inactivity independently contribute to adverse health outcomes, understanding this direction helps clarify causal pathways and might inform interventions.
Public health relevance
- If poor sleep leads to reduced physical activity, sleep health becomes not only a marker of wellbeing but also a potential target to improve PA levels — especially important in aging populations.
- Interventions aiming to improve PA among older adults might benefit from also addressing sleep quality, sleep disturbances, and possible sleep-disordered breathing.
Mechanistic plausibility
- The authors discuss plausible mechanisms: poor sleep may cause fatigue, impaired cognition, low motivation, mood disturbances, or social withdrawal, all of which can reduce inclination toward PA.
- Additionally, SDB (e.g., from snoring or breathing cessation) may impair restorative sleep, potentially leading to daytime sleepiness, reduced energy, and less capacity or desire to engage in physical activity.
Complex interplay with age and sex
- The observation that associations differ by sex and age suggests that sleep’s impact on later physical activity is not uniform — tailored approaches may be required in interventions.

Strengths & Limitations

Strengths

Very large sample size (over 51,000 individuals) covering a broad middle-aged to older adult age range (55–93 years).
Assessment of multiple sleep traits (duration, disturbances, SDB symptoms) rather than just one dimension.
Comprehensive adjustment for a broad range of potential confounders, including comorbidity status, lifestyle factors, BMI, and prior PA (in sensitivity analyses).
Use of sensitivity analyses to test robustness of associations (healthy subset, prior PA adjustment).

Limitations

Self-reported sleep and PA data: both exposures (sleep) and outcomes (PA, sedentary behavior) were based on questionnaires, which may be subject to recall bias and misclassification.
Observational design: cannot establish causality — unmeasured confounding or reverse causation remain possible.
Relatively short follow-up period (1 year). The temporal gap is limited, and overlap between exposure and outcome cannot be fully excluded.
Lack of objective sleep measurements or clinical diagnoses of insomnia / SDB; sleep-disordered breathing symptoms were self-reported, not clinically assessed.
The cohort is mostly of northern European origin and older adulthood; results may not generalize to younger populations or other ethnic groups.

Conclusions & Implications

The study by Uppsala University / Karolinska Institutet researchers (2025) strengthens the case that sleep health is not only consequential for overall well-being, but may also influence individuals’ capacity and habits for physical activity.

Given that physical inactivity and sedentary behavior are major risk factors for cardiovascular disease, metabolic disorders, and reduced quality of life — particularly in older populations — these findings highlight sleep as a potentially modifiable lever in public health interventions aiming to enhance active and healthy aging.

Future research should build on these findings by using objective sleep measures (e.g., actigraphy or polysomnography), longer follow-up, and in more diverse populations. Interventional studies might examine whether improving sleep (quality, reducing disturbances, diagnosing and treating SDB) leads to sustained increases in physical activity and better health outcomes.

Key Takeaways

Among > 51,000 middle-aged and older Swedish adults, poor sleep (long sleep, disturbances, SDB symptoms) was associated with lower odds of walking, bicycling, and exercise the next year, and higher odds of sedentary behavior.
Associations varied by sex and age: e.g., SDB’s association with reduced exercise was stronger in men and in those < 65 years.
The data suggest a bidirectional relationship between sleep and physical activity — poor sleep may contribute to physical inactivity, which in turn may worsen health outcomes.
Given the limitations (self-report, observational design), results should be interpreted with caution; however, they underscore sleep health as a potential target for interventions aimed at increasing physical activity in older populations.