Six years ago I decided to dramatically reduce the amount of time I spent watching TV, and this single intervention (I believe) had a dramatic effect on my life. It liberated a significant amount of time that I could devote to perhaps more useful and rewarding pursuits. You may be thinking that I’m referring to things like writing or exercise. Actually, I’m referring mainly to sleep.
I’d got into the habit of staying up late watching TV in a soft of zombified state. It didn’t seem to matter what I watched either. For instance, on more than one occasion I found myself watching competition poker games in the small hours. The thing is, I don’t even know how to play poker. Somehow, it seems the TV had some irresistible lure, which I finally cured myself of all those years ago. I do watch TV now, but am extremely selective about what I watch (rugby, usually), and I can’t remember the last time I engaged in any late evening viewing.
I was reminded of the fact that I’ve swapped TV viewing for sleep this week on the reading of a letter which appeared recently in the British Journal of Nutrition [1]. The letter, from two people based at the Healthy Active Living and Obesity Research Group (HALO) in Ottawa, Canada, explore the potential links between TV viewing and sleep duration and obesity.
The letter draws our attention to the fact that TV viewing is associated with an increased risk of obesity, while sleep appears to have quite the opposite association. The letter goes on to explore what factors may explain these associations.
So, one factor might be that people who watch a lot of TV are less likely to be physically active. It’s a plausible theory, but it seems there is some evidence to suggest that TV viewing does not put a significant dent in the amount of energy burned through activity. As the letter points out, it is more likely that the most significant factor here is not energy expenditure, but energy intake: individuals watching TV are more likely to see and act on adverts for not very healthy food. I also think the near-constant reminders of food TV ads and programmes can give us make it more likely that we are going to make our way to the fridge or kitchen cupboards for a snack. Also, eating this food in front of the TV runs the risk of us consuming food ‘mindlessly’ – something that may lead to us eating more than we need to satisfy our appetite.
What about sleep? Again, more sleep being associated with a reduced risk of obesity may not make sense at first sight because some may imagine sleep will burn fewer calories than when we’re up and relatively active. However, even if this were the case, it needs to be borne in mind that the longer someone sleeps for, perhaps the less opportunity there is to eat.
Maybe more importantly than this, though, is the evidence cited in the letter relating to the impact of sleep on processes in the body that regulate appetite and therefore food intake. For example, short sleep is associated with higher levels of the appetite-stimulating hormone ghrelin and lower levels of the appetite-sating hormone leptin. Short sleep can also induce insulin resistance, and this might possibly impair transport of glucose into the brain and lead to increased hunger as a result.
Here’s some interesting excerpts from the letter in question:
Although speculative, it is plausible that a few hours of napping on the couch could have a vastly different (and more positive) impact on weight maintenance than an equivalent amount of TV viewing. This raises an obvious question: if you are concerned about your body weight, is it better to sleep through your favourite TV show rather than watching it?
It is perhaps time that clinicians urge their patients to not only reduce their daily amount of TV viewing, but to also replace that TV time with a good night’s sleep. Interventions that focus on increasing sleep time or reducing TV viewing may prove easier to implement than those focused specifically on diet or exercise.
Reducing TV viewing and/or getting adequate sleep require little in the way of resources or expertise, and may therefore be more sustainable than more traditional interventions focused on diet and exercise. If having a good night’s sleep truly is better for your weight than watching TV, this would be a lifestyle modification which may be substantially easier to implement than adopting a new diet or exercise routine. This change of focus is certainly worth consideration, right after a short nap.
So, far fetched though it mat seem, maybe there’s something for us to learn here. Those seeking to attain and maintain a healthy weight might contemplate turning off the TV and getting an earlier night.
References:
1. Saunders TJ, et al. Is obesity prevention as simple as turning off the television and having a nap? Br J Nutr 2012 doi:10.1017/S0007114512002644
