Well, generally speaking, it is very common to have bloodshot eyes after exercise, especially the Cardio exercise. And you should know that Cardio exercise by itself should not cause either bloodshot eyes or red eyes. And an external irritant and an underlying systemic disorder can be the causes after cardio workout. For example, when you have cardio workout, it can lead to high blood pressure. And the high blood pressure can lead to high eye pressure and bloodshot eyes. So you should just be careful about it. Besides, there are also some other common causes include straining during exercise and irritants such as dust or sweat. Anyway, a heavy pressure can cause the blood vessels of the eye to burst. That can be bloodshot eyes.
When you do the cardio workout, you must spend a lot of energy which may make you have the sweat in a large amount. Then the skin of your body may feel dry. The same principle is also suitable for the eyes. The eye nerves will be intense. Every vein in the eyes will look tight. The too dry eyes may easily cause the bloodshot. You should have a good rest now and wait for its release.