So binge-watching is your favourite downtime habit, huh? Well, you might want to reconsider if a study that found marathon viewing may wreak havoc on our health is anything to go by.
A paper published in the Journal of Clinical Sleep Medicine found that people's addiction to watching TV series can lead to, among other things, insomnia, chronic fatigue and obesity, which in turn have a damaging effect on the body's immune system.
Binge-watching in this paper was defined as "watching multiple consecutive episodes of the same television show in one sitting on a screen, be it a television, laptop, computer or tablet" and an average binge-watching session lasted 3 hours and 8 minutes, with 52 percent of binge-watchers viewing three to four episodes in one sitting.
Binge-watchers reported more fatigue, more symptoms of insomnia, poorer sleep quality and greater alertness prior to going to sleep.
Poor sleep in general is associated with lower immune system function and a reduced number of antibodies or "killer cells" that help fight germs.
"If one considers that most of the watching occurs in the evening, that doesn't leave much shuteye," said Nicole Jennings, spokesperson for local pharmaceutical company Pharma Dynamics. She highlighted some of these health effects in detail.
"Watching TV in a dark room for hours on end can really mess up our circadian rhythm (the cycle that regulates physiological processes) and disrupt sleep-wake cycles. The blue light emitted from TVs, PCs, laptops, smartphones and other devices can also reduce the production of melatonin, a hormone that promotes sleep," said Jennings.
Hence binge-watchers may struggle with sleep after the binge.
- Chronic fatigue
Binge-watching may be the reason why you need to reach for that extra cup of coffee to get through the day. That's because sleep fuels your body to keep it functioning properly, and not sleeping properly takes a toll on your body.
Insomnia resulting from marathon viewing may result in chronic fatigue, which is described as extreme fatigue that can't be explained by any underlying medical condition. This fatigue may worsen with physical or mental activity, but doesn't improve with rest, according to the Mayo Clinic.
Marathon-viewing can exacerbate mindless eating and unhealthy snacking, which are both detrimental to your waistline and immunity. Jennings pointed out that it's easier to order pizza than pausing your show for an hour to cook a nutritious meal.
Research by Cornell University's Food and Brand Lab found that action-packed shows such as "The Walking Dead", for example, made participants eat twice as much (98 percent) than those who watched milder talk-show content. Those that watched depressing shows, like the sci-fi drama "Solaris", for example, also ate 55 percent more than participants who watched positive, upbeat programmes.
According to the researchers, action and adventure shows may encourage viewers to eat more, because viewers subliminally try to keep up with the pace of the story. Stress and anxiety experienced during a show also leads to comfort eating.
- Weakened immune system
"Adults need between seven and nine hours of uninterrupted sleep every night in order for the immune system to function optimally. Poor sleep in general is associated with lower immune system function and a reduced number of antibodies or 'killer cells' that help fight germs," explained Jennings.
For example, a binge-watcher's risk of respiratory tract infections (RTIs) such as a cold, sinusitis or tonsillitis increases as a result of lowered immune function.
Junk food also upsets the immune system.
"Fatty, fried foods increase bad cholesterol and can cause inflammation, leading to reduced immunity, while sugar can hinder the body's ability to produce germ-fighting white blood cells that destroy foreign pathogens. Watching your favourite characters drink a beer or smoke a cigarette might also trigger a craving for these substances, which have been proven to lower immunity."
Jennings suggested putting out cut-up fruit and vegetables, or low-carb meals and healthy drinks, if you're planning to watch a TV series.
- Deep vein thrombosis
Furthermore, sitting in the same position while watching hours of TV series contributes to deep vein thrombosis and the formation of fatal blood clots.
A University of Minnesota study published in the Journal of Thrombosis and Thrombolysis, which analysed 15,000 adults based on how they watched television, found that people who watch "very often" run a 1.7 times higher risk of venous thromboembolism (VTE) — or deep vein thrombosis — clots in the legs and pulmonary embolisms.
The danger comes from prolonged sitting and impaired circulation and doesn't seem to be eliminated by exercise during other times or weight levels.
New interventions are needed
A study conducted by researchers in the US found that staying physically active nearly halved the odds of catching cold viruses, and even those that did fall ill didn't suffer too badly.
Jennings also suggested that instead of sitting on the couch, TV addicts should consider watching a series on their cellphone or tablet while walking on the treadmill, stationary bike or rowing machine. "There are different ways to make the occasional marathon TV session healthier, but moderation is key," she pointed out.
And according to Liese Exelmans and Jan van den Bulck, the authors of the binge-watching effects paper, interventions and treatments to reduce alertness before sleep, such as relaxation techniques and mindfulness, could be valuable approaches to target sleep problems associated with binge-watching.
Further, because binge-watching often occurs unintentionally, it has been suggested that streaming services such as Netflix should enable viewers to pre-select their maximum viewing duration before beginning each viewing session to control marathon viewing.