Why Am I Always Cold After Gastric Bypass

Im Freezing! Why Gastric Bypass Causes Patients to be Cold

Body temperature is the result of your body generating and radiating heat. The body is adept at keeping its temperature within a narrow range even though ambient air conditions vary. A normal body temperature is 98.6°F. It is common during the period of rapid weight loss for bariatric patients to feel cold or chilled, even when their temperature reads normal.

People who experience the massive weight loss associated with weight loss surgery experience feeling cold for two reasons: loss of insulation and less energy generation.

Fat is a highly efficient insulator. Consider animals native to cold climates: for example sea lions and polar bears. They are loaded with insulation and thrive in cold climates. When gastric bypass patients follow the rules: eating protein and exercising, the weight lost can only come from fat or stored energy. In effect you are losing your insulation. Less insulation increases the likelihood that you will feel cold.

The second reason for feeling chilled is that the metabolic cell processes are not working as hard as when you were heavier; it takes fewer calories and less energy to maintain and move a smaller body. Think about using an electric mixer: if you are whipping egg whites for a meringue the mixer will do this task effortlessly. But use the same mixer to knead bread dough and it will become warm to the touch, it is working harder because it is moving more mass. The same thing happens with your body; the more mass it must move, the harder it works. As a result more heat is generated.

The body has two well-tuned mechanisms for regulating body temperature: sweating and shivering. What overweight person hasn’t been embarrassed by a sticky bout of sweating at the most inappropriate time? Sweating is a mechanism for cooling your body when it becomes too hot inside. The body rids itself of excess heat by expanding the blood vessels in the skin so the heat may be carried to the surface. When this energy or heat in the form of sweat reaches the skin’s surface it evaporates and helps cool the body.

Gastric bypass patients become more familiar with the second temperature regulator, shivering, as they lose weight. When you are too cold your blood vessels will contract reducing blood flow to the skin. The body responds by shivering which creates extra muscle activity to help generate more heat. If you allow your body to shiver it will begin to feel warmer. But this is also a good clue that it’s time to put on a sweater or turn up the heat. I think most weight loss patients will happily wear a sweater – a sweater is much easier to shed than that insulation we’ve worked so hard to lose!

Most weight loss patients report that their body temperature regulates after their weight is stabilized, usually eighteen to twenty-four months after surgery. Keep in mind your body is rapidly losing weight and the rest of your body’s functions are caught off guard when this weight loss begins. The body’s thermostat needs time to catch up to the weight loss, and it will. Patients who incorporate exercise in their weight loss program experience less chilling than patients who do not exercise.

Copyright © 2005 Kaye Bailey – All Rights Reserved

Feeling Cold after Gastric Sleeve Surgery

Feeling Cold after Gastric Sleeve

Feeling cold is one of the side effects of bariatric surgeries such as a gastric sleeve. The gastric sleeve surgery has become the most commonly performed weight loss surgery in the United States due to its relative safety, effectiveness in achieving significant weight loss and reversing comorbid conditions with the attendant reduction in the cost of healthcare and prolonging the life of obese individuals.

Weight loss surgeries including gastric sleeve can reduce weight by reducing the availability of calorie thus necessitating the mobilization of fat for energy production. This implies that as you lose weight, the quantity of fat in different parts of the body gradually reduces. Fat is known to serve as an insulator. The feeling of cold after gastric sleeve surgery is therefore not unconnected with the function of fat in the regulation of body temperature.

How is heat generated in the body?

Virtually all metabolic reactions in the body are energy dependent. The breakdown of food molecules result in energy production, but due to the inefficiency in harnessing this energy, a considerable amount is lost as (converted to) heat. This heat can either be conserved to maintain the body temperature or dissipated.

How is the body temperature regulated?

Animals maintain their body temperature by various means including hibernation during cold seasons. We can keep our core body temperature despite wide variations in our environmental temperature. The regulation of body temperature in humans is a function of a part of the brain known as the hypothalamus. This area of the brain functions as the thermostat receiving inputs about the body temperature of nerve cells that are identified as thermoreceptors. There are cold and heat receptors in the skin and other inner organs.

When the body temperature is getting low, the cold receptors are stimulated and in turn, send this information to the spinal cord for onward transmission to the hypothalamus. Likewise, elevation of the body temperature above the set point will stimulate the heat receptors, and the information will be transmitted to the hypothalamus. The information, therefore, determines the response of the hypothalamus it receives from the thermoreceptors.

How does the body respond to temperature changes?

The process of heat loss from the body can be by conduction, radiation or evaporation. When the body temperature rises beyond the set point, the hypothalamus sends impulses to the appropriate brain centers which in turn results in vasodilatation of the cutaneous arterioles (small arteries in the skin). This increases the blood flow with heat being transferred to the skin. The consequence is excessive sweating. Evaporation of the sweat from the skin surface results in cooling.

When the body temperature is lower than the setpoint, the response is vasoconstriction and reduction in blood flow to the skin to minimize heat loss. The body can also generate heat by muscle contraction (shivering).

Peculiarity of heat regulation in obese individuals

Obese people often generate a higher amount of heat energy than their healthy weight counterparts. The basal metabolic rate is higher in obese people thus resulting in more heat production. The excess fat in them is a poor conductor of heat and therefore serves as “insulator” preventing obese individuals from losing the excess heat to their environment by conduction. The increase in body mass in them is accompanied by a relatively lower increase in body surface area (because the height remains constant). This implies that obese individuals will lose less heat as heat loss is proportional to the surface area of the skin. In summary, excess fat keeps you warm.

What happens after gastric sleeve surgery?

You generate less energy

Losing weight only means that your body now requires less power to keep you in optimal condition. The basal metabolic rate and energy production reduces, leading to less heat production.

You lose fat

Weight loss occurs after gastric sleeve surgery due to the low-calorie intake. Your body, therefore, turns to the stored fat as a source of energy. The fat under your skin is the first to be used up. The insulation provided by these fat pads is lost leading to more significant heat loss from the body than before.

Hypothalamic response

The cold receptors then pick this information whenever the body temperature is low and send it to the hypothalamus. The body tries to generate heat by muscle contraction leading to shivering, and blood flow to the skin is reduced by vasoconstriction. You may also develop goose pimples from contraction of the smooth muscles associated with hair follicles.

In summary, feeling cold after gastric sleeve surgery is due to low heat production and loss of insulation both as consequences of fat loss. You can keep yourself warm by putting on multiple layers of clothes. It is a transient feeling that you will overcome as your thermoregulation gets adapted to your new weight.

Why Do People Feel Cold After Gastric Sleeve Surgery?

Do You Feel Cold After Gastric Sleeve Surgery?

If you do your research, you’ll find that man who undergoes weight loss surgery such as gastric bypass or gastric sleeve experience this. It’s not unusual to feel cold after gastric sleeve, and it can be considered the number one side effect of having weight loss surgery. You are probably wondering if this is okay and why it happens.

What Contributes to This Change?

There are two main contributors to this issue:

1. Fat Loss

The answer is quite simple as to why patients who undergo weight loss surgery experience this sudden change. When you are eating a high-fat diet and are gaining weight, you build up a layer of fat just underneath the skin. This layer of fat is called subcutaneous tissue and acts as a form of insulation and wards off cold. There are, in fact, many types of fat, but this is the one that begins to thin down over the years after surgery and cause you to have more trouble warding off the extreme cold.

There are in fact also more than one type of fat that will be lost as you go through this change.

2. Less Energy Generated

Once you are thinner, your body no longer needs to work as hard to use as much energy to keep you moving. When you are carrying all of that extra weight; it can be a strain on the body as it has to generate more energy to keep you going. That energy created by your body will make you feel warmer than when you suddenly weigh a hundred pounds less, and there is less effort involved.

Is This Issue Major?

This issue of feeling cold more regularly is not anything to feel concerned about. It is, in fact, a very minor issue to deal with in comparison to risks involved with obesity such as type 2 diabetes, heart disease, and cancer. Just keep in mind that your body has just undergone a procedure that can send it into shock as it readjusts. That adjustment takes time, and you are going to notice the changes as this takes place.

Some say that this issue goes on for a while but then eventually goes away. And many who do not undergo surgery, but eat low-fat diets may experience the same problem as it is to do with losing that layer of fat and not the surgery itself.


The solutions to this problem of feeling cold after gastric sleeve surgery are to simply layer up and wait it out. It is helpful that you take care to keep your body heat at a safe level by wearing more layers or turning up the heat
as needed. You can also buy some comfy hats and mittens to keep your hands and ears more warm and cozy. In time you may very well adjust to where you do not notice such feelings of being colder than usual.

Read About Other Common Issues and What to Expect After Gastric Sleeve


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