The Science of Sleep
By BMJ
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But it’s not entirely clear how much gender, age, weight
(BMI), overall fitness, general health, and exercise type contribute to this
association, they add.
To explore this further, the researchers assessed the
frequency, duration, and intensity of weekly physical activity and symptoms of
insomnia, nightly sleep clocked up, and daytime sleepiness among middle-aged
adults from 21 centers in nine European countries.
Study Findings on Physical Activity
The 4399 study participants (2085 men; 2254 women) were
drawn from the European Community Respiratory Health Survey.
They had answered questions on the frequency and duration
of physical activity at baseline (ECRHS II;1998-2002) and on physical activity,
insomnia symptoms (Basic Nordic Sleep Questionnaire; scale 1-5), sleep duration
and daytime sleepiness (Epworth Sleepiness Scale) 10 years later (ECRHS III;
2011-14).
Participants who reported that they exercised at least
two or more times a week, for 1 hour/week or more, were classified as being
physically active.
Over the 10 year period, 37% (1601) of participants were
persistently inactive; 18% (775) became physically active; 20% (881) became
inactive; and 25% (1082) were persistently active.
Participants in Norway were most likely to be
persistently active, while participants in Spain, followed by Estonia, were
most likely to be persistently inactive.
Persistently active participants were more likely to be
men, younger, and to weigh slightly less. They were also less likely to be
current smokers and more likely to be currently working.
After adjusting for age, sex, weight (BMI), smoking
history, and study center, those who were persistently active were
significantly (42%) less likely to find it difficult to fall asleep, 22% less
likely to have any symptom of insomnia, and 40% less likely to report 2 or 3
(37% less likely) insomnia symptoms.
Insomnia symptoms were also independently associated with
age, female gender, and weight.
As for total nightly hours of sleep and daytime
sleepiness, after adjusting for age, sex, weight, smoking history, and study
center, persistently active participants were most likely to be normal sleepers
while the persistently inactive were least likely to be in that category.
Impact of Consistent Exercise on Sleep
The persistently active were significantly (55%) more
likely to be normal sleepers and significantly less likely (29%) to be short (6
hours or less), and 52% less likely to be long, sleepers (9 hours or more). And
those who became active were 21% more likely to be normal sleepers than those
who were persistently inactive.
The researchers acknowledge that they weren’t able to
objectively assess changes in physical activity levels between the two time
points and that all the elements relied on subjective assessment via
questionnaire.
But they nevertheless conclude: “Our results are in line
with previous studies that have shown the beneficial effect of [physical
activity] on symptoms of insomnia, but the current study additionally shows the
importance of consistency in exercising over time, because the association was
lost for initially active subjects who became inactive.”
Reference: “Association between physical activity over a
10-year period and current insomnia symptoms, sleep duration and daytime
sleepiness: a European population-based study” by Erla Bjornsdottir, Elin Helga
Thorarinsdottir, Eva Lindberg, Bryndis Benediktsdottir, Karl Franklin, Debbie
Jarvis, Pascal Demoly, Jennifer L Perret, Judith Garcia Aymerich, Sandra
Dorado-Arenas, Joachim Heinrich, Kjell Torén, Vanessa Garcia Larsen, Rain Jögi,
Thorarinn Gislason and Christer Janson, 1 March 2024, BMJ Open.
DOI:
10.1136/bmjopen-2022-067197
