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For anyone who has ever flown across multiple time zones, the effects of jet lag feel all too familiar. Somnolence and lethargy, not to mention bigger health issues, are the very real byproducts brought on by jet lag.

At the cellular level in the body, those same adverse health effects come when you disrupt your sleep schedule by staying up later on the weekends. It’s called "social jetlag," a novel and pervasive form of circadian rhythm disruption caused by shifting sleep and wake times to accommodate work and social schedules.

Graham McGinnis, assistant professor of Kinesiology and Nutrition Sciences within UNLV’s School of Integrated Health Sciences, was recently awarded a four-year grant from the National Institutes of Health (NIH) to study the effects of social jet lag and how it contributes to cardiovascular disease.

“We know that everything works on a 24-hour scale, driven by our environment and the cycles of light and dark,” said McGinnis. “Beyond those external cues is a cellular time-keeping mechanism called the circadian clock, which is present in basically all of the body’s cells.”

We spoke with McGinnis about his research, the health implications of social jet lag, and the steps we can take to mitigate its effects on our everyday lives.

Can you talk about the importance of sleep as it pertains to our overall health?

Sleep is so catchy now. Everyone is looking at their sleep. There are even mattress commercials using the term "circadian rhythm." That wasn’t the case even a couple of years ago. 

I think that the boon in sleep awareness started within the sports world as a new frontier in improving performance. Over the last few years, it seems like recovery has become paramount to the conversation of performance, and that includes getting really good sleep. 

And during the pandemic, people who worked in an office setting were sleeping better. They were sort of released from their typical schedule and able to adjust to their own temporal preferences. 

Some of the work we’ve done in my lab has been working with different chronotypes, or your individual preference for mornings or nights. If you’re a night owl, it’s tough to work an office job when you need to be there by 7:30 or 8 in the morning. But all of a sudden you have the ability to work from home, or you’re able to work your own hours, and you end up getting much better sleep. 

OK, so what exactly is ‘social jet lag’?

Simply put, social jet lag is a behavioral pattern resulting from shifting behavior (usually staying up later) on the weekends. Social jet lag is rampant, and occurs in about 80% of people to some extent. Let’s say we go out and take in a little of what the town has to offer, and we stay up three hours later, and sleep in three hours later than we normally would have on a school or work night. Your body is getting blue light and food, among other things, later at night. Well, to your body, it’s the same thing as traveling three time zones. 

What we’ve noticed is that people who have social jet lag tend to be less fit and are usually at higher risk for obesity, diabetes, and cardiovascular-risk factors in general. This can happen in kids, as well. Maybe these kids are up all night on the weekend playing video games and then have to readjust their schedule to wake up early for school on Monday. It’s the same thing.

Since Las Vegas is a 24-hour town, there are residents who work varying schedules throughout the week. How does that affect their health?

Night shift work is not great for our bodies. It has recently been labeled as a probable carcinogen and is also linked to higher rates of diabetes and cardiovascular disease. 

If you work a stable shift, you can take measures to adapt to it and structure your life in a way that’s somewhat synchronized. You can try to time things like nutrition, physical activity, and blue light exposure to keep yourself on one schedule. 

But when things change on a rapid basis, or they’re constantly rotating, it’s really hard to adapt to those changes. If you start your work week on a night shift and then change to a daytime schedule so you can see your family on the weekends, those shift periods are really hard. 

So what’s your advice for the social jet laggers? 

The advice for how to stay healthy when you’re forced to work these kinds of schedules is that healthy behaviors are still healthy behaviors. Keep a good diet and participate in physical activity. These are the typically safe recommendations for good health. 

Where the chronobiology comes into play is when you do these things. What time should I eat? What time should I exercise? That’s what my work is aimed at better understanding.

What are you hoping to discover with your NIH grant?

The idea that we are pursuing is to study how these social jet lag behaviors effect cardiovascular health and to see if we can use timed exercise to reduce or prevent social jet lag. Light, food, and exercise are what we call zeitgebers (German for “time givers”). If we can use exercise at specific times of the day to give the body a cue to normalize the circadian rhythm disruption that occurs during social jet lag, hopefully we can mitigate some of those harmful effects.

How do you envision this research benefiting a city like Las Vegas?

Las Vegas is one of the most 24-hour cities in the world, and I think it leaves a lot of interesting possibilities for human studies among a big shift-working population. We’d like to find ideal times for people to do these behaviors, whether it’s a dietary intervention or an exercise intervention.

We know that exercise is good, but if we time it to the precise time, maybe we can make it even better. That could be a tipping point to help someone reduce the risk of cardiovascular disease or to stave off damage from a heart attack. We need to know when exercise is best for us. Certain tissues could react to exercise differently during a certain time of day, so I want to see if we can time our exercise to elicit the most advantageous responses for the heart. 

If a person shows good behaviors, like exercising in the days leading up to a heart attack, they could reduce the amount of cell death by about 50%. Since the heart has very little regenerative capacity, saving that tissue is paramount to long-term survival. The circadian timing of exercise to prevent heart damage is also an area we are currently investigating.

Any advice on avoiding jet lag for those of us who have stable schedules but long-distance trips planned?

The best advice for traveling to a new time zone is to get up at your destination’s morning time as soon as you can, maybe even before you travel if you want to "pre-habituate" to the new time zone. Get a big meal and lots of daylight at the start of your new day. 

Even if you feel awful, getting into that routine sends a lot of signals to your body and hits all of those 24-hour clocks in different organs and tissue to say, "Now my day starts." If you are trying to tell your body that "This is my day time," or "This is my night time," you have to send it those cues. 

Also, avoid the use of blue light devices before you go to sleep and find a really dark space, even if it’s during the day. Blackout curtains can be very helpful.