Whether you look your age or must struggle to hold back the years depends in part on the levels of certain natural chemicals in your blood, according to new research.
Men judged to be ageing fast by a group of male and female observers tended to have high levels of cholesterol in their blood and excessive haemoglobin, the oxygen-carrying pigment in red blood cells.
Women who looked older to the same observers had lower-than-average levels of bilirubin, a byproduct of the breakdown of red blood cells which forms the chief pigment in the bile. These women also showed signs of higher-than-normal levels of proteins in the blood plasma, as determined by a blood test.
The researchers who made the discovery, reported yesterday in the Postgraduate Medical Journal, admitted they were surprised by the results. Prof Christopher Bulpitt, from Imperial College School of Medicine at Hammersmith Hospital, London, said: "Obviously we were not surprised that grey hair and balding were associated with looking older. But we were quite surprised by the association with things like haemoglobin and cholesterol."
The researchers studied 447 London civil servants, including 129 women, whose ages ranged from 38 to 57. Two female nurses and one male doctor were asked to guess the age of each person according to their first impression. In addition, visual ageing was measured by assessing factors such as baldness, greying and skin elasticity.
The study found that looking older was not related to alcohol consumption, job grade or a range of other chemical substances.
On average, men looked older than they really were by about four months and women looked younger by almost six months. Smokers of both sexes tended to look older.
"We think there might be a vascular connection. The only real hypothesis is that small blood vessels to the skin are damaged, whether by cholesterol or smoking or whatever, and it makes you more wrinkled and looking older," Prof Bulpitt said.
The links may be indirect, he said. For instance, baldness was a genetic trait which might also be indicative of vulnerability to blood-vessel damage.
High levels of haemoglobin and low turnover of red blood cells could both be a sign of poor respiratory function. In a similar way, climbers and walkers who ascend to high altitudes produce more haemoglobin to boost the supply of oxygen to their body cells.