Charlie99
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Johnmpcny -- you didn't ask about freediving after diving, but here's some free advice that is worth what you've paid for it .....
It's not a good idea to do any freediving for the first several hours after diving. The problem is that it is common for you to have some small bubbles in the venous side of the circulatory system for a couple hours after diving. They don't normally cause any problems because they are filtered out by the lungs. People with a heart defect called PFO can sometimes have problem, because the PFO can open up a direct path between the two sides of the heart and let the small bubbles through into the arterial side ... often the opening opens up when coughing or when you hold your breath when lifting something heavy.
Bubbles in the blood on the arterial side can block capillaries, preventing blood from getting to critical bits of your body, like the brain.
When you freedive, the increased pressure will reduce the size of the bubbles in the venous system, thereby letting some of them get past the lungs. Then as you come back to the surface, the bubble will expand back to the larger sizes that can cause problems.
The above cautions don't apply to freediving the day after diving, since you won't have any bubbles in your venous system at that point.
It's not a good idea to do any freediving for the first several hours after diving. The problem is that it is common for you to have some small bubbles in the venous side of the circulatory system for a couple hours after diving. They don't normally cause any problems because they are filtered out by the lungs. People with a heart defect called PFO can sometimes have problem, because the PFO can open up a direct path between the two sides of the heart and let the small bubbles through into the arterial side ... often the opening opens up when coughing or when you hold your breath when lifting something heavy.
Bubbles in the blood on the arterial side can block capillaries, preventing blood from getting to critical bits of your body, like the brain.
When you freedive, the increased pressure will reduce the size of the bubbles in the venous system, thereby letting some of them get past the lungs. Then as you come back to the surface, the bubble will expand back to the larger sizes that can cause problems.
The above cautions don't apply to freediving the day after diving, since you won't have any bubbles in your venous system at that point.