A slump every day after lunch. A craving for something sweet that hits around 4 pm, always at the same time. A waist that thickens while your plate has not changed. Cycles that stretch to forty days or more. And often, when you ask, a parent or a grandmother with diabetes.
Taken one by one, none of this looks like much. Put together in a woman with PMOS, it usually tells the same story. Insulin is working too hard.
Muscle is sugar's biggest customer
After a meal, sugar passes into the blood. The pancreas releases insulin, which opens the door of the cells to let it in. Muscle is by far the biggest customer. When insulin action is measured in the lab, around 80% of the sugar is taken up by muscle (DeFronzo and Tripathy, 2009).
Insulin resistance means the cells respond poorly to that signal. The pancreas makes up for it by producing more, and insulin stays high all the time. With PMOS, that excess pushes the ovaries to make more androgens and encourages fat around the organs. I described this loop in the article on the syndrome's new name, so I will not go over it again here.
Fasting blood sugar, meanwhile, can stay normal for a long time. The pancreas compensates by producing more insulin, and resistance often sets in years before sugar rises in the blood. A blood test that only looks at glucose shows nothing. That is what makes the problem so easy to miss.
Slim does not mean spared
PMOS affects around one woman in eight. Three in four put on weight easily, but one in four stays slim, and she is often diagnosed even later.
In Melbourne, a team measured insulin sensitivity with the gold standard method, the clamp, in 40 women with the syndrome and 33 without. Insulin-sensitising treatments and the pill had been stopped three months before. Insulin resistance was present in 75% of slim women with the syndrome and in 95% of those carrying extra weight. In overweight women without the syndrome, it was 62%. At the same weight, the women with the syndrome were more resistant (Stepto et al., 2013).
The fat that matters here is not the kind you can pinch under the skin. It is visceral fat, around the liver and the gut. It keeps up an inflammation that makes cells even deafer to insulin, and you can have it without being overweight.
The signs that should alert you
No single sign is enough. It is the whole picture that counts.
The first is hunger. Late afternoon cravings and the slump after lunch come when blood sugar rides a rollercoaster, with a big surge of insulin and then a drop.
The second is your waist. It says more about visceral fat than your weight does. The rule is simple, it should stay below half your height. For a woman who is 1.65 m tall, that means under 82 cm. Measure it in the morning, at the level of your navel, without pulling your stomach in.
The third is your family. Diabetes, prediabetes or gestational diabetes on your mother's or your father's side should make you take notice. Genes load the gun. Lack of sleep, stress, sitting all day and processed food pull the trigger.
Finally, the cycles themselves. Long cycles, acne, unwanted hair, very often it is insulin pushing the androgens behind them.
The blood tests to ask for
In my guide, I recommend a check every six months to a year. Fasting glucose and fasting insulin, HbA1c, a lipid panel with triglycerides, vitamin D, and depending on the case testosterone and SHBG, the protein that carries testosterone in the blood.
The 2023 international guideline goes the same way on sugar. It asks for blood sugar to be assessed in every woman at diagnosis, whatever her weight, then every one to three years depending on risk. The most accurate test is the oral glucose tolerance test, a 75 g glucose drink followed by several blood samples. If that test is not possible, fasting glucose and HbA1c will do, knowing they are less accurate (Teede et al., 2023).
On insulin, the guideline is more cautious. Standard insulin tests are considered too imprecise to diagnose insulin resistance. I still keep fasting insulin in the check, for a different reason. It gives you a starting point, and you compare it from one blood test to the next. Along with triglycerides, it often drops clearly within a few months once food and movement change.
Prepare your appointment. Write down the length of your cycles over several months, your symptoms and any diabetes in the family. If you are told everything is fine because you are slim, get a second opinion.
What moves the numbers
Since muscle takes up most of the sugar, muscle is what you put to work first. Every kilo of muscle you gain makes your body a little more sensitive to insulin. Two to three strength sessions a week, full body, with loads that go up little by little.
Sprints add something. Six to eight efforts of 20 to 30 seconds, on a bike, a rower or up a hill, once or twice a week. They empty the sugar stores in your muscles, which then become more sensitive to insulin for the hours and days that follow. And ten to fifteen minutes of walking after lunch and dinner bring blood sugar down clearly, because the leg muscles take up sugar without waiting for insulin.
Your plate does the rest. What goes on it and in what order, I covered in PMOS diet, what to eat to calm insulin. Why you should never cut calories too hard is in PMOS and dieting.
A baseline blood test and a waist measurement noted once a month give you something to compare against. Cycles that get shorter and more regular are often the first sign that insulin is coming down. Your body responds when you give it the means.
This article is for information only and does not replace medical advice.