When may symptoms of carbon monoxide poisoning become noticeable in a diver?

Symptoms of carbon monoxide poisoning can become noticeable during the ascent phase of a dive due to the changes in pressure and breathing patterns. As a diver ascends, the partial pressure of gases in the body decreases, which can lead to a more pronounced effect of carbon monoxide on the diver's physiology. The diver may experience symptoms such as headache, dizziness, confusion, or fatigue as they ascend, which can be misleading as these symptoms can also be attributed to normal exertion or other diving-related factors.

It's important to note that carbon monoxide is a colorless, odorless gas that can be introduced into the body through polluted air or malfunctioning equipment. While a diver could potentially be affected by this gas at any point (including at the surface or during the dive), the ascent often accentuates the symptoms because the diver's body is adjusting to the changes in pressure and is more sensitive to the effects of carbon monoxide.

Early recognition of these symptoms is crucial as they can escalate quickly and may lead to serious health issues if not addressed promptly.