The association between physical fitness and depressive symptoms among young adults: results of the Northern Finland 1966 birth cohort study

Abstract

BackgroundThe effect of physical activity on mental health has been the subject of research for several decades. However, there is a lack of studies investigating the association between physical fitness, including both cardiorespiratory and muscular fitness and depressive symptoms among general population. The aim of this study was to determine the association between physical fitness and depressive symptoms among young adults.MethodsThe study population consists of 5497 males and females, members of the Northern Finland birth cohort of 1966, who at age 31 completed fitness tests and filled in a questionnaire including questions about depressive symptoms (Hopkins’ Symptom Checklist-25) and physical activity. Cardiorespiratory fitness was measured by a 4-min step test and muscular fitness by tests of maximal isometric handgrip and isometric trunk extension. The odds ratios (OR) with 95% confidence intervals (95% CI) for having depressive symptoms were calculated for quintiles groups of physical fitness using the third, median quintile as reference group, and the results were adjusted for potential confounding variables.ResultsDepressive symptoms were most common among males and females in the lowest quintile group of trunk extension test (OR 1.58 and 95% CI 1.07-2.32 in males and OR 1.43 and 95% CI 1.03-2.0 in females) and among males in the lowest quintile group of handgrip strength (OR 1.64 95% CI 1.11-2.42) compared to the reference group. Level of self-reported physical activity was inversely associated with depressive symptoms both in males (OR 1.74 95% CI 1.25-2.36) and females (OR 1.36 95% CI 1.05-1.75). The cardiorespiratory fitness was not associated with depressive symptoms (OR 1.01 95% CI 0.68-1.49 in males and 0.82 95% CI 0.57-1.16 in females).ConclusionsThe results indicate that low level of isometric endurance capacity of trunk extensor muscles is associated with high level of depressive symptoms in both sexes. In males, also poor handgrip strength is associated with increased levels of depressive symptoms. The physical activity level is inversely associated with the prevalence of depressive symptoms among young adults.

The association between depressive symptoms and physical status including physical activity, aerobic and muscular fitness tests in children

“…In other recent studies among older subjects, high DS were reported with worse hand grip strength [11,44]. The result of the present study based on the relationship between static strength and DS is not consistent with the previous studies among adults and older people [10,11,44], but is according to the results of a recent study in a sample of children [12]. As it has been demonstrated consistently, higher grip strength is significantly and positively related to higher adiposity in both children and adolescents [24,25], and higher adiposity is related to higher DS.…”

“…It should be stated that there is little evidence based on the relationship between DS and different components of physical fitness including both CRF and muscular fitness, especially among children [12], and searching the literature just the relationship of DS with aerobic fitness and static strength was observed. For instance, among young adults, poor hand grip strength reported with increased levels of DS just in men participants (but not women) [11]. In other recent studies among older subjects, high DS were reported with worse hand grip strength [11,44].…”

“…For instance, among young adults, poor hand grip strength reported with increased levels of DS just in men participants (but not women) [11]. In other recent studies among older subjects, high DS were reported with worse hand grip strength [11,44]. The result of the present study based on the relationship between static strength and DS is not consistent with the previous studies among adults and older people [10,11,44], but is according to the results of a recent study in a sample of children [12].…”

“…For instance, although significant association has been shown between depression and obesity [45], among homogenous obese adolescents, it was observed that those with elevated DS displayed poorer CRF than those without elevated DS [46]. However, some studies failed to observe significant relationship between CRF and DS [11,18,19]. The inconsistency in results of the studies may be because of some methodological, population being studied and covariates included in the studies.…”

“…However, although the effect of PA on mental health has been the subject of research for several decades, nonetheless, there is a lack of studies investigating the association between different components of physical fitness, including both cardiorespiratory fitness (CRF) and muscular fitness (e.g., strength, speed, power, agility, etc.) and DS [10,11], especially among children [12]. For instance, significant cross-sectional and prospective relationships have been shown between CRF and mental health [12][13][14], and some have reported that high CRF protects against the development of DS [15][16][17].…”