A slow metabolism can make it more challenging to maintain a healthy weight and lose excess fat. But how can you tell if your metabolism is actually slower than it should be? There are several potential signs that your metabolic rate may be sluggish.
What is metabolism?
Your metabolism refers to all of the chemical processes that take place inside your body to keep you alive and your organs functioning normally. These include:
- Breaking down food and beverages into energy
- Turning nutrients from food into new cells and tissues
- Disposing of toxic waste products and substances
- Regulating hormones
- Controlling body temperature
- Maintaining heartbeat and breathing
The number of calories your body burns each day is heavily influenced by your metabolic rate. People with faster metabolisms tend to burn more calories at rest and during activity than those with slower rates.
What causes a slow metabolism?
There are a variety of factors that can potentially slow down your metabolism over time:
Aging
As you get older, the amount of muscle tissue you have tends to decrease while your body fat increases. Muscle burns more calories than fat, even when at rest. The natural loss of muscle mass as you age is a major reason metabolic rate declines with age.
Low muscle mass
People with lower amounts of muscle mass, in general, will have slower metabolic rates. Muscle is metabolically active tissue that contributes significantly to resting energy expenditure. The less muscle you have, the fewer calories you burn.
Weight loss and dieting
When you lose weight, your metabolic rate can slow down. This is because it takes less energy to fuel and move around a smaller, lighter body. Severely restricting calories for an extended period can also cause adaptive thermogenesis, where your body conserves energy by reducing the number of calories burned. This makes it harder to lose weight.
Low physical activity
Being sedentary causes muscle loss and a slower metabolism. Exercise helps build and preserve metabolically active lean muscle mass while burning additional calories. Lack of physical activity reduces overall daily energy expenditure.
Genetics
Some people are simply born with naturally faster or slower metabolisms. You can inherit a tendency towards having a more efficient metabolism that burns fewer calories at rest. However, this doesn’t mean you can’t take steps to speed up a sluggish metabolism.
Medical conditions
Certain medical conditions like hypothyroidism, Cushing’s syndrome, and polycystic ovary syndrome are linked to slowed metabolic rates. Some medications, such as steroids, can also affect your metabolism.
Signs your metabolism may be slow
Here are some indications that your metabolic rate could be slower than optimal:
1. You gain weight easily
If you gain weight rapidly with only small increases in calorie intake or have trouble losing weight even when eating in a calorie deficit, your metabolism may be slow. Difficulty losing weight can happen when you’re burning fewer calories than expected.
2. You have low energy levels
A sluggish metabolism can leave you feeling tired, even if you get enough sleep. Processes like converting nutrients to energy slow down when your metabolism lags, potentially worsening fatigue.
3. You always feel cold
Your body has to burn calories to keep your temperature up. People with slower metabolisms and lower calorie needs often feel chilled more easily. Poor circulation could also play a role.
4. Your digestion is sluggish
Slow digestion and bowel movements can be related to a slower metabolism. Your digestive system doesn’t have to work as hard when burning fewer calories at rest. Constipation is common with an underactive thyroid, which slows metabolism.
5. You have low libido
Hormonal imbalances from conditions causing metabolic changes, like thyroid disorders or menopause, can reduce sex drive. The dip in metabolism from aging and muscle loss contributes too. Poor energy levels and self-esteem when overweight may also lower libido.
6. You have thinner hair
Hair follicles are sensitive to hormones and nutrient deficiencies. Hormonal shifts from thyroid or menopausal metabolic changes can cause hair thinning. Nutrient absorption and circulation may also be affected.
7. Your heart rate is slow
A heart rate lower than 60 beats per minute can signify a sluggish metabolism. When your body is burning fewer calories at rest, your heartbeat doesn’t need to be as rapid. But other non-metabolism related issues can also cause bradycardia.
8. You’re sensitive to cold
If your hands and feet get cold easily, it may be a sign of poor circulation related to a slower metabolism. Your body has to work harder to keep your extremities warm when burning fewer calories.
How to test your metabolic rate
To get a more definitive answer regarding your metabolic rate, you can have it tested. Here are some options:
Resting metabolic rate test
This test measures the number of calories you burn at rest over a certain time period. It requires resting quietly for around 15 minutes while wearing a mask that calculates oxygen consumption. This shows your energy expenditure when your body is at total rest.
Indirect calorimetry
Similar to an RMR test, this evaluates the amount of oxygen used and carbon dioxide expelled to estimate resting energy expenditure. It’s typically done first thing in the morning after an overnight fast.
DEXA scan
Also known as DXA, this scan uses small amounts of X-ray beams to measure fat mass versus lean mass in the entire body and specific regions. As lean mass is more metabolically active, this can provide useful information.
Nutrition tracking
Keeping a detailed food log and tracking your calorie intake and weight changes over several weeks can provide clues to your metabolic rate based on your maintenance calories and weight fluctuations.
Online calculators
There are various online metabolic rate calculators that provide rough estimates of your calorie burn based on inputs like your age, height, weight and activity levels. These are not extremely accurate but can be useful guideposts.
| Test | How it’s Done | Pros | Cons |
|---|---|---|---|
| RMR test | Measure oxygen use at rest via face mask for 15 minutes | Direct measurement of resting calories burned | Doesn’t account for normal daily activity |
| Indirect calorimetry | Measure oxygen use and carbon dioxide expelled at rest, often after overnight fast | Also directly measures resting energy expenditure | Time restricted since fasting required |
| DEXA scan | Uses X-ray beams to measure fat versus lean mass | Quantifies metabolically active muscle mass | Exposes you to a small amount of radiation |
| Nutrition tracking | Record detailed food logs and weight over several weeks | Can approximate your maintenance calories | Self-reported data less accurate |
| Online calculators | Enter your stats like age, weight, height to get calorie estimate | Quick and easy to use | Rough estimate only |
Tips to improve a slow metabolism
If you suspect your metabolic rate is slower than ideal, here are some tips that may help give it a boost:
Exercise more
Make a concerted effort to get more physical activity. Focus especially on strength training to build more metabolically active muscle mass. Shoot for at least 150 minutes per week of moderate exercise.
Reduce stress
Chronic stress and high cortisol can slow metabolism over time. Practice stress management techniques like meditation, yoga, or just taking more time to relax. Getting enough sleep also helps control cortisol.
Eat more protein
Protein requires a lot of energy for your body to break down and digest. Getting 25-30% of your daily calories from protein sources can stoke your metabolic fire.
Drink green tea
Compounds in green tea called catechins may provide a slight boost to metabolic rate, especially when combined with exercise. Drink 2-3 cups per day.
Add probiotics
Probiotic foods like yogurt, kefir and fermented foods help populate your gut with healthy bacteria. Some research shows this diversity may benefit metabolic rate.
Eat spicy foods
Spicy foods containing capsaicin temporarily can increase your calorie burn after meals. Add spices like chili peppers and cayenne to your cooking.
Have smaller meals
Eating smaller meals more frequently keeps your metabolism humming versus larger, less frequent meals. Aim for 4-5 small meals spaced out during the day.
Get enough sleep
Lack of sleep can negatively affect metabolic hormones. Try to get 7-8 hours per night minimum to aid healthy hormone regulation.
Reduce alcohol
Alcohol is high in empty calories and sugars. It’s also inflammatory and can impair sleep. Limit to 1-2 drinks several times per week.
Address health conditions
See your doctor to identify and manage any underlying medical issues or get tested for thyroid problems if suspected. Medication may help if warranted.
Weight train
Lifting weights triggers excess post-exercise oxygen consumption (EPOC) that raises metabolism for hours after your workout. Do full body, multi-joint moves like squats, deadlifts and presses.
| Tip | How it Helps |
|---|---|
| Exercise more | Builds metabolically active muscle and burns extra calories |
| Reduce stress | Controls cortisol, which can slow metabolism |
| Eat more protein | Requires more energy to digest than carbs or fat |
| Drink green tea | Compounds may provide slight metabolic boost |
| Take probiotics | Healthy gut bacteria may benefit metabolism |
| Eat spicy foods | Capsaicin can temporarily increase calorie burn |
| Have smaller, frequent meals | Keeps metabolism stimulated versus larger, less frequent meals |
| Get enough sleep | Lack of sleep disrupts metabolic hormones |
| Reduce alcohol | High empty calories can slow metabolism |
| Address health conditions | Manages issues like thyroid disorders causing slow metabolism |
| Weight training | Builds muscle and causes EPOC calorie burn |
When to see your doctor
If lifestyle efforts don’t seem to make a difference in your metabolism after several months, see your doctor. Getting tested for any underlying conditions causing metabolic changes is important.
Your doctor can check for issues like:
- Thyroid disorders
- Diabetes
- Cushing’s syndrome
- Polycystic ovarian syndrome (PCOS)
- Menopause
- Androgen excess
- Pituitary gland disorders
- Chronic infections
- Autoimmune diseases
- Heart problems
- Anemia
- Nutritional deficiencies
Based on your test results, they may recommend specific treatment options if an underlying condition is found to be causing metabolic changes.
The bottom line
There are many different signs that can indicate your metabolic rate may be slower than optimal, like unintended weight gain, fatigue, feeling cold, and sluggish digestion. Testing your resting metabolic rate directly or getting a DEXA scan to measure body composition can confirm if your metabolism is lagging.
Focus on exercising more, reducing stress, getting enough sleep, eating a protein-rich diet, and managing any medical issues. Making lifestyle changes and getting tested for related health conditions can help give your metabolism a lift long-term.