Associations between walking parameters and subsequent sleep difficulty in older adults: a 2-year follow-up study

Purpose
This 2-year follow-up study aimed to examine the associations between total volume, frequency, duration, and speed of walking with subsequent sleep difficulty in older adults.

Methods
A total of 800 older adults aged 65 years and over participated in the first survey in 2012 and 511 of them were followed 2 years later. The 5-item Athens Insomnia Scale (AIS-5) was used to measure sleep difficulty. Frequency, duration, and speed of outdoor walking were self-reported. Walking speed was assigned a metabolic equivalent value (MET) from 2.5 to 4.5. Total walking volume in MET-h/week was calculated as frequency×duration×speed. Negative binomial regressions were performed to examine the associations between volume and components of walking with subsequent sleep difficulty with covariates of age, sex, education, marital status, living arrangement, smoking, alcohol consumption, mental health, Charlson index, exercise (excluding walking), and sleep difficulty at baseline.

Results
Participants with low walking volume had a higher level of sleep difficulty 2 years later compared with those with high walking volume (incident rate ratios = 1.61, p = 0.004). When speed, frequency, and duration of walking were simultaneously entered into one model, only walking speed was significantly associated with subsequent sleep difficulty adjusting for covariates and baseline sleep difficulty. Sensitivity analyses showed that walking duration emerged as a significant predictor among 3 walking parameters with 2-year changes of sleep scores as dependent variable.

Conclusion
Total amount of walking (especially faster walking and lasting for more than 20 min) is associated with less subsequent sleep difficulty after 2 years among older adults.