Predicting Height is Tricky

030424As someone who had a short mother, I’ve always believed that every adult son will be taller than his mother.  A better rule of thumb is that the likeliest height of your children will be the average of the parents’ height in centimetres, plus seven centimetres for sons, or minus seven centimetres for daughters.

But like many things associated with human beings, accurate prediction is tricky.  Our height is determined to a significant extent by our diet and environment, as well as by our genes.  In fact humans have been growing taller throughout history.  Because of improved diet and lifestyle the average height of males has increased about ten centimetres over the past two hundred years.  At five foot four inches Queen Elizabeth 1 was said to have been strikingly tall.  My wife, who matches her height, is seen as average or even petite as far as height is concerned.

If you want an accurate height measurement it’s important to measure it at the same time every day, because we’re all taller in the morning.  In growing children, growth hormone is secreted in pulses overnight, so that most lengthening of bones occurs in the night time.  For adults, postural compression of the spine under the effect of gravity causes shrinkage during the day.  The combination of disc compression and curvature of the spine can cause a height change of some sixteen millimetres during the course of a day.

So next time, you might check your watch, before giving your height.