instruction:
In medical studies, treatments are tested within a group of study participants. You will be given a sentence of a study report in which your task is to list the phrases that give information about the participants of the study. You should list the phrases in the same order that they appear in the text, separated by commas. If no information about the participants is mentioned, just output "not found". Relevant information about participants include: gender, medical conditions, location, number of people participating. Do not contain participant mentions without relevant information.
question:
To study the effects of physical exercise on biochemical risk factors for ischaemic heart disease 31 healthy middle aged men undertook regular physical exercise for two months and 29 served as controls in a randomised trial .
answer:
31 healthy middle aged men


question:
Both patient groups shared decreased precuneus activation .
answer:
not found


question:
In recent years some studies have been published supporting the efficacy of light exposure , physical activity , sleep control and a Mediterranean diet pattern on the improvement or prevention of depression .
answer:

not found