Sleep and Diabetes: Men and Women Show Opposite Patterns of Risk

Getting enough sleep is important for more reasons than just how energetic you feel the next morning. Sleep affects your weight, your blood pressure, and even whether you will eventually get diabetes. The connection between sleep and the risk of future development of diabetes, however, is very different in men and women. Recent research has found that:

• Men who don't get enough sleep are at greater risk for developing type 2 diabetes.
• Men who get too much sleep are at greater risk for developing type 2 diabetes.
• Women who don't get enough sleep have a lower risk of developing diabetes than women who get normal amounts of sleep or even more.

In the  European Relationship between Insulin Sensitivity and Cardiovascular Disease (EGIR-RISC) study, which involved 800 volunteers ranging in age for 30 to 60 in 14 countries at 19 testing centers in Europe, "normal" sleep was defined as seven hours per night. 

What Is Insulin Resistance, and What Does It Have to Do with Diabetes?

Researchers measured sleep with a device called a single-axis accelerometer, designed to detect movement. They measured insulin resistance, which is predictive of future development of obesity, high triglycerides, high blood pressure, and type 2 diabetes, with a device called a hyperinsulinemic-euglycemic clamp. This "clamp" isn't a physical clamp but a strict control of blood sugar levels. The researchers carefully measured the amount of glucose that they had to give through an IV to raise a volunteer's blood sugar by 125 mg/dl over its normal levels through one vein, while measuring the effects of an insulin drip through another vein.

People who reached high blood sugar levels easily and whose blood sugar levels were slow to fall with the infusion on insulin were said to be insulin resistant. It's possible to be more insulin resistant or less insulin resistant. In people who are insulin resistant but not yet diabetic, the pancreas makes more and more insulin until blood sugars finally go down. This is an effect that the test measures by an actual drip of insulin into a vein. On a day to day basis, insulin "locks" fat in fat cells, so these people are prone to gain weight unless they diet carefully. Eventually the stress of having to produce large amounts of insulin all the time "burns out" the pancreas and diabetes sets in.

How Sleep and Insulin Resistance Differ in Men and Women

The EGIR-RISC researchers started with the observation that people report getting on average 90 minutes to two hours more sleep every night than they did 50 years ago, and that during that time the number of cases of diabetes has doubled. They theorized that excess sleep is either a cause or a result of insulin resistance, which is the driving force behind type 2 diabetes.

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Over thirty sets of researchers had measured blood sugar levels and sleep, but the EGIR-RISC team was the first to measure insulin resistance. When actual insulin resistance was measured they found that in women, getting normal amounts of sleep (not too much and not too little) was associated with greater risk of diabetes, and in men, getting normal amounts of sleep (not too much and not too little) was associated with lower risk of diabetes.

What Should We Do Differently to Prevent Type 2 Diabetes?

“Even when you are healthy, sleeping too much or too little can have detrimental effects on your health,” lead researcher Femke Rutters told the press. “This research shows how important sleep is to a key aspect of health – glucose metabolism.” Unfortunately, this study just tells us that there is a relationship between diabetes and sleep, not what to do about it. Here are a few humble suggestions.

• If you are a man, and you are tired all the time, needing more sleep than you used to, make sure you get your blood sugar levels tested at least once or twice a year even if you don't have diabetes. It's important that your doctor measure your blood sugar levels when you are not fasting at least occasionally. Your pancreas retains the ability to release enough insulin to normalize blood sugar levels overnight for many years after insulin-producing beta cells start dying from the stress of overproduction. By the time your fasting blood sugar levels are high, there is little or no chance or reversing the course of the disease. If you take corrective measures (changes in diet, activity, and maybe a medication like metformin prescribed by your doctor) when your after-meal blood sugar levels are high, then you are more likely to avoid ever developing the full-blown disease.
• If you are a woman, neither a busy lifestyle nor an occasional vacation is likely to cause any harm to your metabolism before menopause. Once you pass menopause, however, then your risk of diabetes changes dramatically with the changes in hormone production. High blood pressure during pregnancy (preeclampsia) and diabetes during pregnancy (gestational diabetes) may not pose any additional risk of diabetes until you go through menopause. PCOS (polycystic ovarian disease) increases risk of diabetes both before and after menopause, but especially after a hysterectomy or oophorectomy (removal of the ovaries). It's also important for you to get at least occasional tests of your blood sugar levels when you aren't fasting. The blood sugar numbers that cause concern when you have eaten in the prior two hours are higher than those that cause concern when you have been fasting overnight, but there are also diagnostic standards for these "post-prandial" blood sugar levels. You will detect diabetes much sooner, when it is still possible to do something about it, if you get both post-prandial and fasting blood sugar testing. Once or twice a year is enough if you don't have a family history of diabetes.

If you are someone who can't become pregnant, your body's reaction to too little sleep or too much sleep may resemble insulin resistance. If you get too little or too much sleep for too long, obesity, blood lipid problems, blood sugar problems, and type 2 diabetes are likely on the way.

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Can you sleep or not-sleep your way to diabetes freedom? Not really. However, if you have apnea, changes in the anatomy of your throat that cause you simply to stop breathing when you sleep, treatment can make a huge difference in your quality of life--and the quality of life of your bed partner. Treating apnea also is linked to a lower risk of diabetes and diabetes complications. Sleep to feel good the next day, but monitor your health on a regular basis.