Ray Peat on Body Temperature and Pulse

Short answer: Ray Peat judged metabolic rate with a thermometer and a watch. He used body temperature together with the resting pulse, measured on waking and again after breakfast, because either number alone can be misleading.

What Ray Peat wrote about temperature and pulse

The method comes from Broda Barnes, who argued that the temperature taken before getting out of bed is the best basis for diagnosing thyroid function. Source: TSH, temperature, pulse rate, and other indicators in hypothyroidism

Peat added the pulse. He met people with clear hypothyroid symptoms and a normal temperature, and others whose resting pulse was very high and came down to normal when they took thyroid. Source: TSH, temperature, pulse rate, and other indicators in hypothyroidism

He cites a finding that healthy and intelligent groups of people average a resting pulse of about 85 beats per minute, and less healthy groups about 70. Source: TSH, temperature, pulse rate, and other indicators in hypothyroidism

He described the after-breakfast test. In a healthy person both temperature and pulse rise after breakfast. In a very hypothyroid person the morning numbers can be held up by cortisol and adrenaline, and fall once food brings those down. Source: TSH, temperature, pulse rate, and other indicators in hypothyroidism

Weather can fool the thermometer. In hot, humid air it takes very little metabolism to hold 98.6°F, so the pulse tells more. In the cold, the temperature of the hands and feet can be a better sign than the mouth. Source: TSH, temperature, pulse rate, and other indicators in hypothyroidism

Hormones move the thermostat. Estrogen lowers body temperature and progesterone raises it. Serotonin, melatonin and polyunsaturated fats lower it too. Source: Multiple sclerosis, protein, fats, and progesterone

A higher body temperature improves deep sleep. He notes that a hot bath, or just warming the feet, works like thyroid in that respect. Source: Thyroid, insomnia, and the insanities: Commonalities in disease

What he suggested in practice

• Take temperature and pulse on waking, and again after breakfast.
• Read them together.
• Watch the hands and feet in cool weather.

Where he wrote about it

This topic comes up in 55 of the articles on his site. These are the most relevant ones:

• TSH, temperature, pulse rate, and other indicators in hypothyroidism · original on raypeat.com ↗
• Hot flashes, energy, and aging · original on raypeat.com ↗
• Multiple sclerosis, protein, fats, and progesterone · original on raypeat.com ↗
• Thyroid, insomnia, and the insanities: Commonalities in disease · original on raypeat.com ↗
• Salt, energy, metabolic rate, and longevity · original on raypeat.com ↗
• Stem cells, cell culture, and culture: Issues in regeneration · original on raypeat.com ↗
• Oils in Context · original on raypeat.com ↗
• Aging, estrogen, and progesterone · original on raypeat.com ↗

My take

A healthy thyroid makes you feel warm, especially in the hands and feet. My quick check is temperature, pulse, cold hands, mood and whether you have at least two bowel movements a day.

Quick answers

What pulse rate did Ray Peat consider healthy?

He cites groups of healthy, intelligent people averaging about 85 beats per minute at rest, compared with about 70 in less healthy groups.

What body temperature did Ray Peat look for?

He refers to 98.6°F as normal and, following Broda Barnes, to the waking temperature as the main sign, but always read together with the pulse.

Why measure after breakfast?

Because stress hormones can hold the morning temperature and pulse up in a hypothyroid person. After eating, those hormones fall and the true state shows.