I wouldn't be surprised if whatever HGH boost you supposedly got from sauna is on a par with the Test boost you might get from regularly consuming almonds.
Only way to really increase HGH in adulthood is to inject it.
But I'll echo that sauna and ice bath several times per week is a godsend. The ice bath in particular is useful for reducing soreness, improving sleep, regulating breathing, and relaxing into discomfort. If you do combat sports and you several times per week you'll notice a 10-20% decrease in soreness, which is a lot.
Only way to really increase HGH in adulthood is to inject it.
But I'll echo that sauna and ice bath several times per week is a godsend. The ice bath in particular is useful for reducing soreness, improving sleep, regulating breathing, and relaxing into discomfort. If you do combat sports and you several times per week you'll notice a 10-20% decrease in soreness, which is a lot.