How Do You Track Body Temperature for Metabolism?
How Do You Track Body Temperature for Metabolism?
TL;DR
Your waking body temperature shows your metabolic rate. Under 97.8°F means suppressed metabolism. Above 98.0°F means healthy metabolism. Take it first thing when you wake up. Under your tongue. Before you move or drink anything. Track it daily for three weeks. You're looking for patterns and trends.
Your energy crashes at 3 PM every day.
You eat clean. You sleep eight hours. You exercise. Nothing changes.
Blood tests say you're fine. But you feel like shit.
Your body temperature tells a different story.
Your metabolism is an engine. Temperature is the gauge showing how hot it runs. A cold engine means low power output.
Why Does Temperature Matter?
Your thyroid controls your metabolic rate. More thyroid hormone in your cells means more energy production. More energy production means more heat.
Temperature is the output signal. It shows what's happening at the cellular level.
Normal waking temperature is 97.8°F to 98.6°F. Measured under your tongue. Before you get out of bed.
Below 97.8°F? Your metabolism is running slow. Your cells aren't making enough energy. Your thyroid hormone isn't getting into cells efficiently. Learn how seed oils block thyroid function.
Above 98.0°F consistently? You're in the healthy range. Your cells are making energy. Your thyroid is working.
Ray Peat emphasized this for fifty years. He found temperature more reliable than blood tests. You can have normal TSH and low cellular metabolism. Your labs look fine but your cells are cold.
The thermometer doesn't lie.
How Do You Track It?
Buy a basic digital thermometer. Five euros. Nothing fancy.
Every morning when you wake up, before you get out of bed, put it under your tongue. Close your mouth. Wait for the beep.
Write down the number. Date and temperature. That's it.
Do this every day for three weeks.
Don't obsess over one reading. One cold morning doesn't mean anything. One warm morning doesn't mean you're cured.
You're looking for patterns.
Week one: all readings between 96.8°F and 97.4°F? Low metabolism.
Week two after changing your diet: climbing to 97.6°F? You're recovering.
Week three: steady at 98.0°F or higher? Metabolism is healthy.
Track pulse too. Same time. Count beats for 60 seconds. Or 15 seconds and multiply by four.
Healthy pulse at rest: 75-85 beats per minute.
Below 70? Usually correlates with low temperature. Low metabolism.
Above 85 at rest? Could be stress. Could be overtraining. Context matters.
Temperature and pulse together paint the picture.
What Affects Your Reading?
Time of day matters. Morning temperature is lowest. It climbs during the day. Don't compare your morning reading to your afternoon reading. Compare morning to morning.
Consistency matters more than precision. Same thermometer. Same time. Same method. Under the tongue. Before you move.
Some people measure armpit temperature. Fine. Just stay consistent. Armpit reads about 0.5°F lower than under tongue.
Women: track through your cycle. Temperature rises slightly after ovulation. That's progesterone. Normal. You're still looking for the baseline trend. Are you consistently below 97.8°F even at your peak? Low metabolism.
Illness throws it off. Fever means infection. Not metabolic rate. Skip tracking when you're sick. Resume when you're better.
Alcohol the night before suppresses it. Your reading will be low the next morning. Not because your metabolism crashed. Because alcohol suppresses thyroid temporarily.
Context. Always context.
What Do You Do With the Data?
If your temperature is consistently low, you have options.
Change your diet. Stop eating seed oils. Add saturated fats. Eat more carbs. Track for two weeks. Does temperature climb?
Adjust your eating schedule. Some people's temperature drops when they skip breakfast. Eat within an hour of waking. Does it help?
Check your stress. High cortisol suppresses thyroid. Are you sleeping enough? Overtraining? Working 80-hour weeks? Temperature won't recover until you manage stress.
Get proper thyroid labs. If temperature stays below 97.8°F after diet and lifestyle changes, get tested. Full panel. TSH, free T3, free T4, reverse T3, antibodies. You might need medication.
But try the simple interventions first. They work for most people.
Temperature gives you feedback in real time. Blood tests take weeks to schedule. Temperature takes 60 seconds every morning.
FAQ
Q: What if my temperature is 96.5°F every morning? A: That's very low. Change your diet first. Cut seed oils. Add butter and carbs. Track for two weeks. If it doesn't budge, see a doctor. You might have hypothyroidism.
Q: My temperature jumps around a lot. 97.2°F one day, 98.4°F the next. Why? A: Normal fluctuation is about 0.3-0.5°F. Bigger swings usually mean inconsistent measurement (different time, different method) or your metabolism is unstable. Track what you ate the day before. Look for patterns.
Q: Can I use an infrared forehead thermometer? A: Less accurate. They measure skin temperature, not core. Use an oral digital thermometer under your tongue. More reliable.
Q: Should I track temperature if I'm on thyroid medication? A: Yes. It shows if your dose is right. If you're on levothyroxine but temperature stays low, you might need a dose adjustment or the addition of T3. Talk to your doctor.
This isn't medical advice. I'm not your doctor. You're responsible for your own body. If you suspect thyroid disease, see a professional.
Want to know what your temperature means?
The SugarSaint course includes temperature and pulse tracking templates, interpretation guides, and protocols to optimize your metabolism.
[Get the Course – $297]
Not sure where to start?
[Take the 2-Minute Quiz]