Exposure to cold is unpleasant, but used properly, cold exposure is an extremely potent tool for improving health, exercise capacity, and fat burning.
Cold causes an increase in metabolic rate to produce heat to try and counteract the effects of cold resulting in increased calorie/fat burning. However, exposure to cold has a far deeper biological and hormonal impact on the body.
Cold Therapy (CT) is proven to increase adiponectin levels. Adiponectin is a hormone that stimulates fatty acid oxidation in muscle cells by activating AMP-activated protein kinase. Or in simple terms – cold increases adiponectin, adiponectin burns fat.
CT also lowers blood sugar levels by burning glucose as heat, and increases glucose uptake into muscle helping speed up recovery times. Clearance of excess blood glucose into muscle helps prevent blood sugar being converted into fat by the liver. Meaning a cold shower after a high carb meal might prevent a lot of the negatives from high sugar intake!
CT also activates conversion of regular body fat (known as white adipose tissue or WAT) into brown adipose tissue (BAT – aka Brown Fat). BAT is very different than typical fat in that it is dense in energy producing mitochondria (hence its brownish color) and utilizes body fat (typically from the belly and back) as its fuel source.
Cold and Norepinepherine
Norepinepherine (NE for short) is an excitatory neurotransmitter that is one of the primary initiators of fat burning. NE is the key initiator of the Sympathetic Nervous System’s (SNS) Flight or Fight Response.
The Flight or Fight Response is something we have all experienced anytime we are really scared such as almost getting into a serious car accident. If you recall an experience like that you will remember that you are often shaking after the danger has passed.
Shaking occurs because when you perceive a threat the brain pushes out high levels of NE. High levels of NE stimulate a cascade of effects including:
Increased heart rate
Increased oxygen consumption
Shut-down of digestive tract while pushing more blood to muscles for action
Increased pupil dilation
Increased mental focus
Reduced perceived exertion, pain, and inflammation.
Release of fatty acids and glucose from storage to fuel high levels of muscular activity.
High levels of NE also stimulate the adrenal glands to secrete epinephrine (EP). EP is also known as adrenaline. NE and EP are chemically almost identical with NE being a neurotransmitter and EP being a hormonal version.
This strong SNS response prepares you for action!
Even brief exposure to extreme cold (20 seconds at 40°F, 4.4°C) causes a 200-300% boost in norepinephrine that lasts for an hour. As stated above increased NE stimulate release of EP as well. You experience a noticeable boost in vigilance, focus, attention, and mood, along with improved oxygen delivery, blood circulation, antioxidant function, mitochondrial biogenesis, and reduced perceived exertion, pain, and inflammation.
Cold and Sleep
Although cold exposure initially causes a strong sympathetic nervous response (like what occurs during any high intensity exercise) later the body re balances and there is an increase in your Parasympathetic Nervous System (PNS) response as a reaction to this stimulus.
Your PNS is basically your rest/sleep/repair mode. So the increased PNS response to cold exposure after the acute SNS response helps with sleep quality.
Takeaway – Cold Showers can be an effective tool to boost exercise performance and fat burning. for those seeking lower body fat levels. Do 5-10 minute sessions in the morning, dry off and then warm-up and exercise – you will feel rocket charged, have a better workout and burn more fat!
To learn more about all the positive effects of using cold exposure for positive health and fitness benefits listen to this great podcast on the subject: https://www.foundmyfitness.com/episodes/cold-stress-hormesis