Vitamin K plays essential roles in bone and heart health, and it’s also been shown to boost exercise capacity. While some vitamin K1 (found mostly in green plants) can be converted into K2 in the body, that conversion can be limited. On average, men need at least 120 micrograms (mcg) per day, but one study on exercise performance found that taking 300mcg of K2 for four weeks and then reducing it to 150mcg for another four weeks increased cardiac output – the amount of blood the heart pumps through the circulatory system in a minute – by 12 per cent.
Sources of Vitamin K
Cooked kale: 418mcg per 100g
Broccoli: 141mcg