Nov 5, 2026 · 39 min
Brief cold and heat exposure may strengthen metabolic resilience
Essentials: Cold & Heat Exposure for Metabolic Health | Dr. Susanna Søberg
The episode connects repeated, tolerable temperature stress with brown-fat activity, insulin sensitivity, and practical approaches to metabolic health.
- 1Cold exposure triggers shivering, brown-fat activity, and other thermogenic responses that may support insulin sensitivity.
- 2Winter-swimming research links roughly 11 weekly minutes of combined cold and sauna exposure with improved insulin sensitivity.
- 3The Søberg principle favors ending contrast sessions with cold, prompting the body to generate heat after exposure.
Don't miss
Susanna Søberg introduces her principle of ending alternating heat-and-cold sessions with cold to extend post-exposure heat production.
The brief
Dr. Susanna Søberg explains how cold shock, hyperventilation, shivering, and brown fat turn discomfort into a measurable thermogenic response.
The conversation compares showers, immersion, head dunking, cold air, and cooler bedrooms, emphasizing skin exposure and cooling speed over one universal protocol.
Winter-swimming and sauna research links roughly 11 minutes per week of combined exposure with improved insulin sensitivity, while inflammation findings remain part of the discussion.
The standout practical idea is the Søberg principle: end a contrast session with cold so muscles and brown fat keep generating heat afterward.
Søberg’s guidance favors repeated short exposures and adaptation, offering a flexible framework rather than a single required temperature, duration, or schedule.
What was said on this episode
26 statements · 23 positive · 1 negative · 2 neutral
- Susanna Søbergon cold exposurePositive0:56
Cold exposure should produce uncomfortable cold to trigger cold shock.
“you should get uncomfortable cold”
Listen at 0:56
- Susanna Søbergon cold exposure adaptationPositive1:39
Repeated cold exposure reduces the hyperventilation response through adaptation.
“you can kind of like get adapted to it”
Listen at 1:39
- Susanna Søbergon brown fatPositive3:28
Activating brown fat increases metabolism.
“when you activate that, that's going to increase your metabolism”
Listen at 3:28
- Susanna Søbergon cold showersPositive4:01
Cold showers may increase metabolism through brown-fat activation.
“it could be good also for increasing metabolism in theory”
Listen at 4:01
- Susanna Søbergon skin cold receptorsNeutral5:08
Skin cold receptors directly signal brown fat.
“there's also a direct pathway from the co-receptors in the skin to the brown fat”
Listen at 5:08
- Susanna Søbergon cold exposurePositive9:21
Cold exposure trains metabolism and increases insulin sensitivity.
“It's training of your metabolism. And that's going to increase what's called the insulin sensitivity.”
Listen at 9:21
- Susanna Søbergon repeated cold exposurePositive11:24
Repeated cold exposure increases brown-fat activation.
“you will have more activation of your brown fat”
Listen at 11:24
- Susanna Søbergon cold exposurePositive13:07
Long-term cold exposure may lower blood pressure and heart rate.
“The longer outcomes, the long-term outcomes could be that you lower your blood pressure and have a lower heart rate.”
Listen at 13:07
- Susanna Søbergon cold exposurePositive13:39
Cold is the strongest stressor for activating brown fat.
“cold is the most potent stressor activator of our brown fat”
Listen at 13:39
- Susanna Søbergon skin temperature changePositive14:06
A skin temperature change can activate brown fat.
“you can activate your brown fat just by getting a temperature change on your skin”
Listen at 14:06
- Susanna Søbergon sleeping at 19 degrees CelsiusPositive15:07
Sleeping at 19°C activates and increases brown fat.
“if you sleep in 19 degrees Celsius, then you will activate your brown fat and you will grow your brown fat”
Listen at 15:07
- Susanna Søbergon sleeping at 19 degrees CelsiusPositive15:53
One month sleeping at 19°C increased insulin sensitivity.
“The subjects were sleeping at 19 degrees from one month, had increased insulin sensitivity.”
Listen at 15:53
- Susanna Søbergon brown fatPositive16:55
Brown-fat activation can reduce white fat.
“the brown fat can in that way decrease our unhealthy fat, which is the white fat”
Listen at 16:55
- Susanna Søbergon cold-water exposurePositive24:38
Cold water need not be extremely cold to activate metabolism.
“it doesn't have to be that cold to be good enough and enough to activate our metabolism”
Listen at 24:38
- Susanna Søbergon winter swimmingPositive25:09
Winter swimmers had increased insulin sensitivity versus controls.
“the winter swimmers had an increased insulin sensitivity”
Listen at 25:09
- Susanna Søbergon winter swimmingPositive26:15
Winter swimmers cleared blood glucose faster than controls.
“the winter swimmers had a faster glucose clearance in the bloodstream”
Listen at 26:15
- Susanna Søbergon cold and sauna exposureNeutral26:50
The studied cold-and-heat regimen totaled about 11 minutes weekly.
“this ended up being 11 minutes in total per week”
Listen at 26:50
- Susanna Søbergon cold and heat exposurePositive27:31
Small amounts of cold and heat exposure can provide health benefits.
“you don't have to expose yourself very much to the heat or very much actually to the cold to get this healthy benefits”
Listen at 27:31
- Susanna Søbergon excessive cold and heat exposureNegative28:31
Excessive cold or heat exposure may increase cardiovascular disease risk.
“if you overdo it, you exhaust the cells and that will increase your risk of cardiovascular disease also”
Listen at 28:31
- Susanna Søbergon inflammationPositive31:11
Reducing inflammation may decrease lifestyle diseases.
“if we can decrease inflammation, in the body, we will decrease modern lifestyle diseases”
Listen at 31:11
- Susanna Søbergon ending contrast exposure with coldPositive33:17
Ending contrast exposure with cold forces endogenous heat production.
“When you end on the cold, you force your body to heat up by itself.”
Listen at 33:17
- Susanna Søbergon ending contrast exposure with coldPositive33:51
Ending on cold extends the body’s thermogenic exercise for hours.
“you have an exercise for your body going on for hours afterwards”
Listen at 33:51
- Susanna Søbergon winter swimmingPositive34:48
Winter swimmers showed greater post-exposure brown-fat activation and skin temperature.
“they had more activation of the brown fat, higher temperature”
Listen at 34:48
- Susanna Søbergon temperature changesPositive35:45
Temperature changes strengthen cells by challenging adaptation.
“the changes in temperature is what is strengthening your cells in the body”
Listen at 35:45
- Susanna Søbergon cold-water exposurePositive37:10
Water temperatures up to 12°C can activate brown fat.
“It could be all up to 12 degrees Celsius. You're going to activate your brown fat anyways.”
Listen at 37:10
- Susanna Søbergon cold-water exposurePositive37:28
People need not use extremely cold water continuously; varying temperature is sufficient.
“You don't have to. I don't think it's necessary to expose yourself to that. cold temperature all the time, but vary it a bit.”
Listen at 37:28
Statements are attributed to the speaker as said on the episode and reflect their view at the time, not PodLume's. They are not advice.
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