The early morning alarm, followed by a hectic routine and eventual rush out the door are all too familiar to most working people, especially those with kids. Then Saturday comes along to make everything all right with the promise of one thing: sleeping in.

This contrast in routine and sleep schedule may be normal, but is it harmful to your health? New research suggests that it might be.

Two studies in recent years examined the sleep habits of working adults and found that those who have variations in sleep patterns, such as waking up early on weekdays and then going to bed later and sleeping in on weekends, may be related to metabolic health risk.

A study in the Journal of Clinical Endocrinology & Metabolism found that people who had a greater difference between sleep schedules for workdays and non-workdays were more likely to have poor cholesterol levels, larger waist circumference, higher body mass index (BMI) and greater insulin resistance.

Additionally, a study in the journal SLEEP examined working, middle-aged women and found that frequent shifts in sleep timing may be related to higher BMI and insulin resistance.

So what’s the answer? Do we lobby our bosses and school administrators for later start times? Do we – gasp! – get up early on weekends?

The bottom line, according to Roy Kohler, MD, who specializes in sleep medicine at SCL Health in Montana, is to aim for seven hours of sleep per night, and don’t worry too much about which seven hours.

The findings in these studies suggest that those with greater shifts in sleeping patterns might be at greater risk for conditions such as diabetes, obesity and heart disease. Now, the key phrase is “might be.” Study of differences in sleep patterns between workdays and non-workdays, known as “social jet lag,” is very young. And these studies only show an association between social jet lag and metabolic health, not that these shifts cause poor metabolic health.

“I think the headline ‘Waking up early on workdays may harm metabolic health,’ that’s music to a lot of people’s ears who have trouble getting out of bed in the morning,” says Dr. Kohler, but science is seldom that black and white.

Dr. Kohler notes that a body of research shows that people who get less sleep tend to be heavier, eat more, have a higher BMI, and are more likely to be diabetic. And while waking up earlier on workdays may mean less sleep, that might not always be the case. Maybe some of you disciplined few make your bedtime on weeknights. Kudos to you!

Dr. Kohler advises his patients to focus on getting seven hours of sleep each night however you can. More research backs up that advice than the idea that your bedtime should be the same every night. 

“Consistent sleep of seven hours a night is what’s recommend for adults just for daytime functioning—being on task, being alert for the day and being able to concentrate and not be so moody and tired during the day,” says Dr. Kohler.

It may be that these shifts in wake and bed times are detrimental to your health, but the research is young. So make seven hours of shut-eye your primary goal and then worry about cleaning up your sleep schedule. Dr. Kohler says to determine when you need to wake up, work backward from there to figure out when you need to go to bed, and stick to that schedule.

“You want to start with that firm wake up time, and that’s usually the pivot on which all the recommendations get made,” says Dr. Kohler.