A cold can be bad luck and unsafe since you will have a problem clearing your ears and sinuses while descending or ascending.  If you have just had a cold you should be safe but diving with a cold or congested head can be unsafe.  You can also be at a higher risk of getting an agonizing reverse squeeze, or worse, a ruptured eardrum.

However, there are degrees of colds. You can dive in the initial stages provided you can clear your ears. If you can, get as many dives in as possible, even though the initial stages may make you feel lousy.

Once a cold reaches your chest you should give up because you will not be able to feel a mucus plug and no dive is worth bursting a lung.  If you have a fever with your cold or flu it can increase your body's metabolism, which can cause you to use up air more quickly, and possibly cause you to be disoriented or have a panic attack. You should not dive while taking medications that state they cause drowsiness or impair your motor abilities.  Be sure to take caution when taking any medication since most cold remedies contain aspirin to make you feel better.  For diving you may want to avoid combination medications and go for a decongestant only, as this is the symptom that you most want to overcome. Nasal sprays directed up the nostrils can also be used to relieve sinuses and sometimes Eustachian tubes.  Even though they may make you feel better on the surface they can wear off while diving so be careful when choosing a medication.

How do you prevent getting that cold?

Can they be prevented?  There is no evidence to suggest that cold viruses are linked to cold weather. Simply that the conditions for transmission conditions are more favorable. You don't get colds by getting cold, or wet. However, colds do like a cold nose so you should try to at least keep it warm.

The cold bug is highly communicable. Colds and flu are easily transmitted by a simple sneeze, which can be known to travel many feet and simply avoiding people may not be enough. Touching infected people or even items they have touched is another way cold bugs can infect you. You help these cold bugs get in your system when you touch your eyes or nose so be sure to avoid these actions and wash your hands frequently.

There is an incubation period so you may not get away after exposure to a known sufferer.

Avoiding infected people or snifflers is difficult and possibly pointless because by the time the cold comes out they may be over the contagious stage, you just don't know so there's no point in making things worse by worrying.

Avoiding Colds

Everyone has a different trick for avoiding colds. One such idea is dose yourself up with Vitamin C. Getting plenty of sleep the week before a trip is far more effective, but could be negated by the strain of traveling which inevitably doesn't help you fight bugs off.

Of course there is no cure. You must sit it out until your immune system works out how to overcome this invader, and that takes a minimum of five days. There are many favorite remedies but remember a cold, while diving, is that you may be able to get down but the mucus plug will not clear on the way up and the only other way out is through the eardrum. It must be a judgment call of course but in my experience provided you can get down the first thirty feet you will be able to get back up. Providing you get down the odds are you will get back up as long as you can control your ascent rate by means of a line. I would not like to do an emergency ascent in such circumstances.

Medications

Most over the counter cold remedies can cause drowsiness while they mask the cold symptoms.  For diving you should avoid these “cocktails” and use a decongestant only if you decide you have to dive.  The best rule of thumb is to discuss potential medications with your doctor before you have a cold since they know your medical history as everyone reacts differently.

Checklist:

Unless you can answer "yes" to all of these questions, you should not dive. No dive is worth your health, safety or life. Stay healthy and enjoy diving another day.

  • Can you breathe easily through both sides of your nose?
  • Have you gone at least two hours without having to blow your nose to clear it?
  • Can you equalize your ears with minimal effort on land?
  • Has it been at least a day since you have had fever, chills or sweats?
  • If someone asked you to engage in a physical activity, would you feel up to it physically?
  • Have you gone at least two hours without coughing?
  • If you are taking medicine, will it last until at least two hours after the dive is scheduled to end?