the older we get , the worse our immune system functions, and it declines more each year. at a certain point it becomes so weak that a simple cold can mean the end. in 1999 researchers at the university of bologna in italy published an epidemiological study that suggests you can halt the decline of the immune system by doing resistance training and by taking extra vitamin d.
the researchers took blood samples from 62 men and women aged between 90 and 106. they put cancer cells in the blood. and then the researchers measured how long it took the immune cells to eliminate of the cancer cells.
the older the participants in the study were, the fewer immune cells they had in their blood. but, the more muscle mass the participants had in their upper arms, the more immune cells they had in their blood. so muscles, it would seem, counteract the negative effect that aging has on the immune system.
another factor was the vitamin d level. the more vitamin d there was in the participants' blood, the more immune cells the researchers found. the figure above shows this.
although more muscle mass did indeed mean more immune cells, muscle mass did not influence the effectiveness with which the immune cells killed the cancer cells. the researchers did observe a relationship with vitamin d: the higher the vitamin level, the more cancer cells the immune cells were able to kill.