Is It Safe to Exercise After Diving?
January 2001
By Ernest Campbell
When Is It Safe to Exercise After Diving?
Will the residual nitrogen in my system from a dive affect my cardiovascular system when I do an aerobic workout the next day?
via e-mail
We get asked this question a lot, especially from dedicated runners, swimmers, hikers and gym rats. It takes about 24 hours to eliminate residual nitrogen from your body. There is some debate about whether exercise, especially strenuous activities such as running or mountain climbing, is risky during that period of time. Those who advise divers not to exercise immediately after diving say that it might increase the chances of bubble formation from residual nitrogen levels.
The research on exercise after diving can be contradictory. There are some inconclusive reports that point to physical stress as the cause of DCS in some divers who exercise after diving. But there is also evidence that exercising while decompressing is helpful in reducing decompression accidents.
How Do I Keep Bugs From Bugging Me?
What insect repellent do you recommend to prevent mosquito, sand fly and other insect bites? I collected over 30 bites in five days of otherwise great diving in the Dominican Republic, despite head-to-toe spraying with Off! insect repellent.
via e-mail
There are no repellents that are 100 percent effective in preventing insect bites; if you only got 30 bites in five days in the Dominican Republic, I"d say that the Off! was 95 percent effective. Your choices:
DEET: N,N-diethyl-3-methylbenzamide (better known as DEET) is the most effective and best-studied insect repellent currently on the market and is the active ingredient in Off! When DEET-based repellents are used in combination with permethrin-treated clothing (see below), protection against bites of nearly 100 percent can be achieved. Plant-based repellents are generally less effective than DEET- based products.
HourGuard: The 3M Company developed a slow-release, polymer-based product named HourGuard that contains 35 percent DEET; this is the repellent used by U.S. military personnel. It's distributed by Amway Corp.
Skin-So-Soft: No-see-ums and sand flies use a different method to achieve their blood-sucking--by chewing the skin with mouth parts and an anti-coagulant. This is the reason sticky skin creams are effective at preventing their bites. Avon Skin-So-Soft can be mixed with Off! in a spray bottle, and is fairly effective, though not 100 percent effective. Avon now markets products under the Skin-So-Soft label that contain an EPA-recognized repellent. These products have very short half-lives and are also effective against some mosquitoes.
Bite Blocker: Bite Blocker is a plant-based repellent that combines soybean oil, geranium oil and coconut oil in a formulation that has been shown to be nearly 100 percent effective against mosquito bites.
Permanone: Permethrin (one common brand name is Permanone) is usually sold as a spray; it does not use DEET or citronella. It is sprayed on clothing, insect nets and the like (it is not applied topically). Permanone is found in outdoor sports and fishing/hunting stores and catalogues.
Did DCS Cause My Chronic Back Pain?
**In the last few years, my back has been "going out," landing me in bed for about two days. The last two episodes occurred on a dive boat, just after a dive. Both times, I felt a "pop" in my lower back. I am 39 and in good health. I work out three to five days a week, riding a stationary bike and lifting weights.
An orthopedic specialist says I have some arthritis in my right hip joint. He is concerned that the chronic pain is because of a diving-related injury. He said I might have a form of bends, and each subsequent dive is aggravating the injury further. I have an MRI scheduled in a month to see if bubbles are concentrated in my lower back area. What do you think?**
via e-mail
Since you describe your back "going out" with a pop, I don't think your back problem has been caused by a decompression accident, especially since you don't mention any neurological symptoms. I suspect chronic lumbosacral strain or arthritis. The orthopedist is correct in noting that your hip problem could be due to diving since there's the possibility of dysbaric osteonecrosis in divers who have made poorly controlled deep dives. This would show up on an X-ray, and should be relatively easy to diagnose.
Bubbles wouldn't show up in diagnostic testing as they don't hang around very long and are absorbed by the body. Their "footprints" remain as scars from the resulting tissue damage and as inflammation, which occurs with a decompression accident. Subsequent diving does seem to concentrate new bubbles in or around the areas of previous damage. The MRI might show damaged areas, but you would surely have had some neurological indication of this.
Was My Son's Elbow Pain Caused by DCS?
**Shortly after surfacing from an 86-foot dive, my 12-year-old son complained of moderate to severe pain in his elbow. Our computers were one dot in the yellow and our ascents and safety stops were by the book. I experienced no DCS symptoms. After the required surface interval, we made a second dive to 56 feet, even though my son's elbow still hurt.
When we returned to the boat, my son's elbow pain had stopped and didn't return. Is it possible he was slightly bent on his first dive, and that he "decompressed" on the second dive? Also, is there anything about a growing child's physiology that would predispose him to DCS?**
via e-mail
It is entirely possible that your child had bubbles in his elbow, particularly if there was no trauma or previous history of arthritis. Joint pain from DCS would improve with recompression but would most likely have returned and worsened after the ascent from the second dive. This is not something you can prove, although an MRI of the elbow might be good to have in case of further difficulty.
There are issues to consider with children diving, such as diving's potential effects on lung, bone and other developing tissue. Children divers should stick to dive profiles that minimize their DCS risk to eliminate possible injury to growing tissues, such as the growth plates of bones. There are no studies that indicate that these growth plates (epiphyseal plates) are a particular problem--just suspicion that an area of increased vascularity might be more susceptible to bubbles. Since the damage that can be done to bone is directly proportional to the length of time at depth, time and depth should be restricted in the growing teenager. A teenager's ascent rates and safety stops should be carefully monitored.
Also of concern is patent foramen ovale, which can allow venous bubbles in the right side of the circulation to cross over into the arterial side and cause clinical bends or arterial gas embolism. It is known that the rate of closure of a patent foramen ovale in the heart is highly variable and in some children, it will not have closed by age 7. This is something that your pediatrician can check.
Help! My Reg Makes Me Gag
As a new diver (12 dives), I have a problem with a strong gag reflex when the regulator is in my mouth. Any ideas about a solution?
via e-mail
You could try mirror biofeedback. Using a mirror, start with a snorkel, inhale to the count of 4 and exhale to the count of 6 (relax as you exhale). Watch your face relax in the mirror. If you see your face, jaw, eyes, neck and shoulders relax, then you are doing it right. Then try the same exercise with tongue depressors in your mouth. Finally, try it with your reg mouthpiece.
It may be that the mouthpiece of your reg needs to be trimmed. Remove any excess silicone that extends back to your back teeth and trim the excess that hits the roof of your mouth. Another option is to swim laps in the pool with a snorkel until the gag reflex goes away. If you only experience it with a regulator mouthpiece and not with a snorkel (having a virtually identical mouthpiece), it may be that the gagging is anxiety-related, and not anatomical or physiological in nature.
Some dentists sprinkle sugar or salt on the tongue or palate before making dental impressions to inhibit the gag reflex. A topical anesthetic works well--especially Dyclone, which is longer-acting.
Finally, if these suggestions don't work for you, consider getting a full face mask.
Can I Dive with a Cold?
I canceled a recent dive trip because I had a bad cold. Was that really necessary?
via e-mail
You probably did the right thing. Nasal congestion and blockage can lead to sinus and middle ear barotrauma. And the resulting sinus infections and middle ear damage and infections can cause hearing loss and balance problems.
Travel Exercise
Here's a light workout to help maintain your dive fitness when you're away from home (and the gym):
Warm-Up Run in place or do jumping jacks for three to five minutes. Slowly increase your rate.
Stretching Exercises
Shoulder, arm and side. Clasp your hands and put them behind your head. Slowly turn to the right, alternating to work the opposite arm. Do 10 times on each side.
Lower back. Lie down on the floor and pull knees to chest. Slowly lower your knees to the right. Hold for one minute. Reverse.
Torso. From seated position, place right foot outside of left knee. Extend left arm outside of right knee, turn to the left and look behind you. Reverse.
Hamstring, Lower back and hips. Sit on the floor with legs spread in front, pull right foot up to the left inner thigh. Bend and reach to the left knee. Alternate.
Strength Exercises
Push-ups. If unable to do a push-up, leave knees on the floor throughout the exercise. Do 10 to 35.
Shoulder raise (shoulder, upper back). Standing in an erect position with feet apart, raise arms directly up from sides as far as allowed by flexibility. Lower slowly. Weighted objects in each hand will increase the benefit (towels, books, shoes, loaded hangers). Do 10 to 30.
Sit-ups (abdomen). Lie on back with knees bent and hands on abdomen. Tuck chin, curl upper body, lifting shoulders off the floor. Return slowly to starting position.
Lower body (hips, buttocks, thighs, calves). Stand erect with hands on back of head and feet apart. Stride forward until other knee just touches the floor and push back up immediately. Alternate right and left leg. Do 5 to 15 on each leg.
Cool Down Similar to the warm-up, but at an easier pace.
_Ernest S. Campbell, M.D., FACS, makes his home in Orange Beach, Ala. He is a retired surgeon, avid diver and webmaster of "Diving Medicine Online" (www.scuba-doc.com).
Please send your dive medicine questions to RSD, 6600 Abercorn St., Suite 208, Savannah, GA 31405. Fax: (912) 351-0735. E-mail: edit@scubadiving.com._
January 2001
By Ernest Campbell
When Is It Safe to Exercise After Diving?
Will the residual nitrogen in my system from a dive affect my cardiovascular system when I do an aerobic workout the next day?
via e-mail
We get asked this question a lot, especially from dedicated runners, swimmers, hikers and gym rats. It takes about 24 hours to eliminate residual nitrogen from your body. There is some debate about whether exercise, especially strenuous activities such as running or mountain climbing, is risky during that period of time. Those who advise divers not to exercise immediately after diving say that it might increase the chances of bubble formation from residual nitrogen levels.
The research on exercise after diving can be contradictory. There are some inconclusive reports that point to physical stress as the cause of DCS in some divers who exercise after diving. But there is also evidence that exercising while decompressing is helpful in reducing decompression accidents.
How Do I Keep Bugs From Bugging Me?
What insect repellent do you recommend to prevent mosquito, sand fly and other insect bites? I collected over 30 bites in five days of otherwise great diving in the Dominican Republic, despite head-to-toe spraying with Off! insect repellent.
via e-mail
There are no repellents that are 100 percent effective in preventing insect bites; if you only got 30 bites in five days in the Dominican Republic, I"d say that the Off! was 95 percent effective. Your choices:
DEET: N,N-diethyl-3-methylbenzamide (better known as DEET) is the most effective and best-studied insect repellent currently on the market and is the active ingredient in Off! When DEET-based repellents are used in combination with permethrin-treated clothing (see below), protection against bites of nearly 100 percent can be achieved. Plant-based repellents are generally less effective than DEET- based products.
HourGuard: The 3M Company developed a slow-release, polymer-based product named HourGuard that contains 35 percent DEET; this is the repellent used by U.S. military personnel. It's distributed by Amway Corp.
Skin-So-Soft: No-see-ums and sand flies use a different method to achieve their blood-sucking--by chewing the skin with mouth parts and an anti-coagulant. This is the reason sticky skin creams are effective at preventing their bites. Avon Skin-So-Soft can be mixed with Off! in a spray bottle, and is fairly effective, though not 100 percent effective. Avon now markets products under the Skin-So-Soft label that contain an EPA-recognized repellent. These products have very short half-lives and are also effective against some mosquitoes.
Bite Blocker: Bite Blocker is a plant-based repellent that combines soybean oil, geranium oil and coconut oil in a formulation that has been shown to be nearly 100 percent effective against mosquito bites.
Permanone: Permethrin (one common brand name is Permanone) is usually sold as a spray; it does not use DEET or citronella. It is sprayed on clothing, insect nets and the like (it is not applied topically). Permanone is found in outdoor sports and fishing/hunting stores and catalogues.
Did DCS Cause My Chronic Back Pain?
**In the last few years, my back has been "going out," landing me in bed for about two days. The last two episodes occurred on a dive boat, just after a dive. Both times, I felt a "pop" in my lower back. I am 39 and in good health. I work out three to five days a week, riding a stationary bike and lifting weights.
An orthopedic specialist says I have some arthritis in my right hip joint. He is concerned that the chronic pain is because of a diving-related injury. He said I might have a form of bends, and each subsequent dive is aggravating the injury further. I have an MRI scheduled in a month to see if bubbles are concentrated in my lower back area. What do you think?**
via e-mail
Since you describe your back "going out" with a pop, I don't think your back problem has been caused by a decompression accident, especially since you don't mention any neurological symptoms. I suspect chronic lumbosacral strain or arthritis. The orthopedist is correct in noting that your hip problem could be due to diving since there's the possibility of dysbaric osteonecrosis in divers who have made poorly controlled deep dives. This would show up on an X-ray, and should be relatively easy to diagnose.
Bubbles wouldn't show up in diagnostic testing as they don't hang around very long and are absorbed by the body. Their "footprints" remain as scars from the resulting tissue damage and as inflammation, which occurs with a decompression accident. Subsequent diving does seem to concentrate new bubbles in or around the areas of previous damage. The MRI might show damaged areas, but you would surely have had some neurological indication of this.
Was My Son's Elbow Pain Caused by DCS?
**Shortly after surfacing from an 86-foot dive, my 12-year-old son complained of moderate to severe pain in his elbow. Our computers were one dot in the yellow and our ascents and safety stops were by the book. I experienced no DCS symptoms. After the required surface interval, we made a second dive to 56 feet, even though my son's elbow still hurt.
When we returned to the boat, my son's elbow pain had stopped and didn't return. Is it possible he was slightly bent on his first dive, and that he "decompressed" on the second dive? Also, is there anything about a growing child's physiology that would predispose him to DCS?**
via e-mail
It is entirely possible that your child had bubbles in his elbow, particularly if there was no trauma or previous history of arthritis. Joint pain from DCS would improve with recompression but would most likely have returned and worsened after the ascent from the second dive. This is not something you can prove, although an MRI of the elbow might be good to have in case of further difficulty.
There are issues to consider with children diving, such as diving's potential effects on lung, bone and other developing tissue. Children divers should stick to dive profiles that minimize their DCS risk to eliminate possible injury to growing tissues, such as the growth plates of bones. There are no studies that indicate that these growth plates (epiphyseal plates) are a particular problem--just suspicion that an area of increased vascularity might be more susceptible to bubbles. Since the damage that can be done to bone is directly proportional to the length of time at depth, time and depth should be restricted in the growing teenager. A teenager's ascent rates and safety stops should be carefully monitored.
Also of concern is patent foramen ovale, which can allow venous bubbles in the right side of the circulation to cross over into the arterial side and cause clinical bends or arterial gas embolism. It is known that the rate of closure of a patent foramen ovale in the heart is highly variable and in some children, it will not have closed by age 7. This is something that your pediatrician can check.
Help! My Reg Makes Me Gag
As a new diver (12 dives), I have a problem with a strong gag reflex when the regulator is in my mouth. Any ideas about a solution?
via e-mail
You could try mirror biofeedback. Using a mirror, start with a snorkel, inhale to the count of 4 and exhale to the count of 6 (relax as you exhale). Watch your face relax in the mirror. If you see your face, jaw, eyes, neck and shoulders relax, then you are doing it right. Then try the same exercise with tongue depressors in your mouth. Finally, try it with your reg mouthpiece.
It may be that the mouthpiece of your reg needs to be trimmed. Remove any excess silicone that extends back to your back teeth and trim the excess that hits the roof of your mouth. Another option is to swim laps in the pool with a snorkel until the gag reflex goes away. If you only experience it with a regulator mouthpiece and not with a snorkel (having a virtually identical mouthpiece), it may be that the gagging is anxiety-related, and not anatomical or physiological in nature.
Some dentists sprinkle sugar or salt on the tongue or palate before making dental impressions to inhibit the gag reflex. A topical anesthetic works well--especially Dyclone, which is longer-acting.
Finally, if these suggestions don't work for you, consider getting a full face mask.
Can I Dive with a Cold?
I canceled a recent dive trip because I had a bad cold. Was that really necessary?
via e-mail
You probably did the right thing. Nasal congestion and blockage can lead to sinus and middle ear barotrauma. And the resulting sinus infections and middle ear damage and infections can cause hearing loss and balance problems.
Travel Exercise
Here's a light workout to help maintain your dive fitness when you're away from home (and the gym):
Warm-Up Run in place or do jumping jacks for three to five minutes. Slowly increase your rate.
Stretching Exercises
Shoulder, arm and side. Clasp your hands and put them behind your head. Slowly turn to the right, alternating to work the opposite arm. Do 10 times on each side.
Lower back. Lie down on the floor and pull knees to chest. Slowly lower your knees to the right. Hold for one minute. Reverse.
Torso. From seated position, place right foot outside of left knee. Extend left arm outside of right knee, turn to the left and look behind you. Reverse.
Hamstring, Lower back and hips. Sit on the floor with legs spread in front, pull right foot up to the left inner thigh. Bend and reach to the left knee. Alternate.
Strength Exercises
Push-ups. If unable to do a push-up, leave knees on the floor throughout the exercise. Do 10 to 35.
Shoulder raise (shoulder, upper back). Standing in an erect position with feet apart, raise arms directly up from sides as far as allowed by flexibility. Lower slowly. Weighted objects in each hand will increase the benefit (towels, books, shoes, loaded hangers). Do 10 to 30.
Sit-ups (abdomen). Lie on back with knees bent and hands on abdomen. Tuck chin, curl upper body, lifting shoulders off the floor. Return slowly to starting position.
Lower body (hips, buttocks, thighs, calves). Stand erect with hands on back of head and feet apart. Stride forward until other knee just touches the floor and push back up immediately. Alternate right and left leg. Do 5 to 15 on each leg.
Cool Down Similar to the warm-up, but at an easier pace.
_Ernest S. Campbell, M.D., FACS, makes his home in Orange Beach, Ala. He is a retired surgeon, avid diver and webmaster of "Diving Medicine Online" (www.scuba-doc.com).
Please send your dive medicine questions to RSD, 6600 Abercorn St., Suite 208, Savannah, GA 31405. Fax: (912) 351-0735. E-mail: edit@scubadiving.com._
