Carried out by researchers at Glasgow University, the study analysed data on 391,089 participants taken from the UK Biobank, a large, long-term study that includes data on all-cause mortality, cardiovascular disease (CVD) and cancer incidence, along with television viewing, computer screen time, grip strength, fitness and physical activity.
The team found that both types of screen time — leisure time spent watching a television or time in front of a computer screen — were significantly associated with all health outcomes, with higher levels of screen time associated with a higher risk of all-cause mortality, cancer, and CVD.
However, screen time had almost double the impact on the risk of death, cancer, and CVD in those who had low grip strength or low fitness levels compared to those who had the highest levels of fitness and grip strength.
A similar association was also observed between physical activity and all-cause mortality and cancer incidence.
The team noted that the use of self-reported screen time and physical activity data may have impacted the accuracy of the findings, and as an observational study no conclusions can be made about cause and effect.
However, they added that the results suggest that increasing strength and fitness may provide some protection against the negative health effects of too much time spent sitting down in front of a screen.
“Our study shows that the risks associated with sedentary behavior are not the same for everyone; individuals with low physical activity experience the greatest adverse effects,” commented corresponding author Dr Carlos Celis.
“This has potential implications for public health guidance as it suggests that specifically targeting people with low fitness and strength for interventions to reduce the time they spend sitting down may be an effective approach.”
“While fitness testing can be difficult in healthcare and community settings, grip strength is a quick, simple and cheap measure, therefore it would be easy to implement as a screening tool in a variety of settings,” Dr Celis added.
The results can be found published online in the journal BMC Medicine. — https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-018-1063-1AFP-Relaxnews