From an interview with German Professor Frank Sommer:
Linko1) He states that many "Men vs. Women" health tests are pharmaceutical tests, which bar women of childbearing age from participating to prevent damage to potential children. This means Males are being measured against Preteen Girls and older Women, and exclude Women at the peak of their fitness.
2) He cites how men, culturally, don't like their strength/capability/fitness called into question, because this is seen as demasculinizing. It's the reason men in general don't visit the doctor for health problems, are discouraged from worrying about their weight/appearance, and that whole cliche where "Real Men don't stop and ask for directions," etc.
3) Lacking cultural disincentive to monitor and maintain their health, health conditions in women are primarily prevented, whereas men treat conditions after they've been exacerbated. This leaves Women in general healthier and more fit than the average man.
4) XY chromosomes are genetically "weaker" than XX chromosomes, which can lead to a higher incidence of men manifesting genetic problems than Women. BONUS BIO-FACTS: The Y chromosome originated as a mutated and damaged form of the X chromosome, and they are still more prone to further damage. Similarly, the "Female" phenotype is actually the baseline that humans default to, when hormones are not introduced; "Female" is the template which the "Male" phenotype is an altered, and limited/reduced form of.