London, May 24 (IANS): Want to spend more time watching television? If so, increase your fitness level and grip strength, else the screen time can double the risk of mortality, cardiovascular disease and cancer, warned a study.

According to researchers, increasing the levels of strength and fitness may nullify the adverse health effects of spending a large portion of leisure time sitting down and watching TV or computer screen.

"Our study shows that the risks associated with sedentary behaviour are not the same for everyone; individuals with low physical activity experience the greatest adverse effects," said Carlos Celis from the University of Glasgow in the UK.

"This has potential implications for public health guidance as it suggests specifically targeting people with low fitness and strength for interventions to reduce the time they spend sitting down may be an effective approach," Celis added.

The study, published in the journal BMC Medicine, included data from 391,089 participants.

The researchers considered measuring grip strength, as they suggest that it could be an efficient way to target individuals who may benefit most from public health interventions to reduce screen time.

"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," Celis explained.