Eleven Minutes of Cold Dips Plus Sauna Time Was Linked to Better Blood Sugar Control
The routine used one to two minute dips and about an hour of sauna per week, and the study cannot separate the two effects.
Andrew Huberman · Essentials: Cold & Heat Exposure for Metabolic Health | Dr. Susanna SøbergAbout 11 minutes a week in cold water, plus about 57 minutes in a sauna, was linked to better blood sugar control in experienced winter swimmers.
The swimmers, studied by researcher Susanna Søberg, had two to three seasons of winter swimming behind them. Two or three times a week, they took three one to two minute dips in outdoor water, ranging from about 15 degrees Celsius down to 2 to 4 degrees, alternating with two 10 to 15 minute sauna sessions at about 80 degrees, and ending cold.
Compared with matched controls, the swimmers were more sensitive to insulin. They produced less insulin, both after fasting and after a sugary glucose drink, yet cleared sugar from the blood faster, with lower levels after two hours.
The result comes from the combination, and the study cannot separate cold from heat. Søberg says the point is that brief is enough, and that overdoing cold and heat can exhaust cells and raise cardiovascular risk.
Questions people ask
Would the cold dips work without the sauna?
No. The swimmers alternated three short dips with two sauna sessions and always ended cold, so the study tested the combination. Separate research on cool sleeping and cooling vests also links mild cold to brown fat and insulin sensitivity, but this 11-minute result included heat.
Can a beginner expect the same effect?
The study cannot say. All the swimmers had two to three seasons of regular winter swimming, and were already adapted to cold. Beginners may respond differently, and should start very briefly and never swim alone in cold open water.
Does this mean cold plunges prevent or treat diabetes?
No. Better clearance with less insulin is a healthy pattern, but this was a small study of healthy adapted swimmers compared with controls. It does not prove prevention or treatment, and people with diabetes or heart conditions should talk to a doctor before trying cold plunges or saunas.