Body operating parameters

Home | The Machinery | Physical Body |

The table below summarises typical and “ideal” body operating parameters.  They will vary between individuals so don’t worry if you aren’t “ideal“; these are just guidelines for consideration.


A few people have noted that the specific heat of water (ie the amount of energy needed to raise a given amount of water by a certain temperature) has a minimum at close to the ideal operating temperature of humans and other warm blooded animals.  See curve below.  There doesn’t seem to be any particular reason for this.  Note that water is an excellent substance for helping the body maintain a state of homeostasis.


There are plenty of web sites that provide the ideal body weight based on your height and age.  The body mass index (BMI) is quoted as being the best measure – and we should be somewhere between 18.5 and 25.

Blood pressure is easy to measure at home with the right equipment, and a reading around 120/80 is normal and healthy.

Blood pH is slightly alkaline and the body keeps it within a narrow range.  Much has been written about the value of alkalising foods as being more healthy than acid-forming foods, but most of this goes on in the gut and doesn’t directly affect the pH of the blood.  Blood pH is affected by Carbon Dioxide levels, and slow deep breathing helps to remove Carbon Dioxide from the blood which increases alkalinity (Carbon Dioxide dissolves in the blood making is slightly acidic).  I have seen statements suggesting that white blood cells, which fight disease in the body, work more effectively in more alkaline conditions, but I have been unable to substantiate this from any formal research study.

The resting heart rate is a good indication of health, and now that Fitbits and similar devices are so widely available, it is easy to monitor this yourself over a long period of time.

When we sleep our breathing rate is close to 12 breaths per minute (for healthy adults).  Most adults have a resting breathing rate in the region of 15 – 18 breaths per minute, whereas those who practise yoga and meditation and other breathing exercises will breath at 4 – 6 breaths per minute.  Breathing matters.  Note the linkage back to the pH level of the blood, based on the levels of Carbon Dioxide (not Oxygen).