Circadian Rhythm, Exercise, Depression, And Feedback Loops

Hi folks, welcome!

He doesn’t look as though he chose to make the effort that day, or maybe the sculptor wasn’t very happy. From:



Quote for fun: “Happiness is a choice that requires effort at times.” Apparently from Aeschylus. This is really really really true! If there are degrees of truth, that is!






Whilst tweeting the other day I was reminded of an event that occurred during my training at the Bristol University Veterinary School, in England a long time ago.

The University of Bristol, England, a long time ago! From:

A friend of mine – a very bright chap, intellectually that is! – was thrown out of medical school because of his failure to attend scheduled examinations. He contested this decision by claiming that the medical school conducted many of his examinations in the middle of the night, when was sound asleep. He explained that he had elected to follow a 36-hour rather than the standard 24-hour day, which he considered to be his right as a British citizen. This he did, not by shortening the length of an hour to 2/3 of a standard hour, but by having a 3/2 times as long a ‘day.’ He proposed to the university that the medical school was being completely unreasonable in refusing to adjust his examination schedule to fit his chosen 36-hour day. He lived this schedule for years, and was still doing so when I graduated from the veterinary school. The last time I saw him was as I visited early one morning Greenwich Mean Time, but he was just going to bed so that was the end of that.

My friend seemed to live with the dogged belief that we should each be able live our life in any unobjectionable manner we desire, not being tied down by other people’s unreasonable habits or rules. Clearly, this is a formula for social disaster and poor health given the relationship between our 24-hour day and the rotation of the earth.

This reminds me of a quote by George Bernard Shaw:

“The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.”

Did this behavior by my friend, as the unreasonable man, lead to progress? Possibly, as he may have moved into a more suitable career and led a very productive and happy life. I lost track of him, however, as I was locked into my boring old 24-hour day and it became hard to maintain our friendship in the face of this quotidian frequency disconnect. These events contain examples of the feedback loops that run our lives, of which there are many millions.

Do A (turn up for examination) => stay in Medical School; stay in medical school => invited to turn up for more examinations. This is a positive feedback loop.


Do B (Not turn up for examinations) => not invited to further examinations =>no further examinations, therefore you cannot do B as you are not failing to turn up for examinations to which you are not invited (you might argue this point). This is a crude example of a negative feedback loop.

The world in which we live, and the bodies that we use to live in it, abound with feedback loops. The more you tweet the more tweets you receive, and the more easily you can tweet some more, for instance. In here lie the seeds of addiction, which can tweet and twuff your life away! In fact, positive feedback loops can get us into big trouble, such as this Japanese proverb, “man takes a drink, drink takes a drink, drink takes a man!” This is an example of a positive feedback loop with negative consequences. Then again, happiness makes you (not Aeschylus, apparently) smile, and smiling causes you to feel happy and smile some more, thus being a positive feedback loop with positive consequences.

One set of feedback loops that can be a real challenge to anyone are those that lie between exercise and depression. If you feel depressed, which we all do from time to time, you certainly don’t feel like working out. In fact, you might prefer to eat instead:

However, if you force yourself and do work out you generally feel better afterwards, and sometimes you feel a lot better! This is a positive feedback for feeling better, and a negative feedback for your level of depression. Alternatively, you can avoid working out and trigger the negative feedback of depression <=> no exercise. How do we break this terrible loop? If you have true clinical depression you should seek help. If you are just mildly ‘down’ get a life, force yourself, and just do some exercise you like. It works every time for me. Having a coach can help, as who wants to pay a coach and not do the workouts, or have to tell your coach that you wimped out – not me, that’s for sure!

The real trick is to find out what motivates you. Having a coach helps in my case! Some people want a reward, such as an ice cream, but they would be well-advised to count the calories in and out to be sure that there is a net benefit. Others need to analyze their workouts to see how they are doing and to be assured that they are achieving their goals. In the latter case, there is a great free tool at, along with a workout challenge of the sexes thrown in to boot!

So! Make an effort and be happy!




  1. So you like dead Greeks. So do I.

    Being an economist I have a favourite dead Greek.

    In his history of the Persian wars he quotes the Athenian state’s efforts at tax collecting to finance the rebuilding of Athens after the victory at Salamis. The Athenian admiral Themistoclese (check spelling) arrived at Andros with ships to collect tax after they had been plundered by the retreating Persians.
    He told the Andronians he had with him two powerful gods their names being “Persuasion” and “Force”. The Andronians welcomed him and his gods and told him that the had two more powerful gods and their names were “Bankruptcy” and “Debt” and the man who had defeated the mighty Persian empire sailed away with no tax revenues totally defeated by the Andronians and their gods.

  2. I really like that story!

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Disclaimer: As a veterinarian, I do not provide medical advice for human animals. If you undertake or modify an exercise program, consult your medical advisors before doing so. Undertaking activities pursued by the author does not mean that he endorses your undertaking such activities, which is clearly your decision and responsibility. Be careful and sensible, please.