…according to an article at MedPageToday. The 300+study participants were at high risk of Alzheimer’s dementia due to family history. The protective dose of exercise was at least 7.7 MET per hour/week. Please comment if you can translate that into something practical! Click for the definition of MET at About.com.
Tag Archives: exercise
People with diabetes may have specific issues that need to be taken into account when exercising.
Retinopathy, an eye disease caused by diabetes, increases risk of retinal detachment and bleeding into the eyeball called vitreous hemorrhage. These can cause blindness. Vigorous aerobic or resistance training may increase the odds of these serious eye complications. Patients with retinopathy may not be able to safely participate. If you have any degree of retinopathy, avoid the straining and breath-holding that is so often done during weightlifting or other forms of resistance exercise. Vigorous aerobic exercise may also pose a risk. By all means, check with your ophthalmologist first. You don’t want to experiment with your eyes.
DIABETIC FEET AND PERIPHERAL NEUROPATHY
Diabetics are prone to foot ulcers, infections, and ingrown toenails, especially if peripheral neuropathy (numbness or loss of sensation) is present. Proper foot care, including frequent inspection, is more important than usual if a diabetic exercises with her feet. Daily inspection should include the soles and in-between the toes, looking for blisters, redness, calluses, cracks, scrapes, or breaks in the skin. See your physician or podiatrist for any abnormalities. Proper footwear is important (for example, don’t crowd your toes). Dry feet should be treated with a moisturizer regularly. In cases of severe peripheral neuropathy, non-weight-bearing exercise (e.g., swimming or cycling) may be preferable. Discuss with your physician or podiatrist.
Low blood sugars are a risk during exercise if you take diabetic medications in the following classes: insulins, sulfonylureas, meglitinides, and possibly thiazolidinediones and bromocriptine.
Hypoglycemia is very uncommon with thiazolidinediones. Bromocriptine is so new (for diabetes) that we have little experience with it; hypoglycemia is probably rare or non-existent. Diabetics treated with diet alone or other medications rarely have trouble with hypoglycemia during exercise.
Always check your blood sugar before an exercise session if you are at risk for hypoglycemia. Always have glucose tablets, such as Dextrotabs, available if you are at risk for hypoglycemia. Hold off on your exercise if your blood sugar is over 200 mg/dl (11.1 mmol/l) and you don’t feel well, because exercise has the potential to raise blood sugar even further early in the course of an exercise session.
As an exercise session continues, active muscles may soak up bloodstream glucose as an energy source, leaving less circulating glucose available for other tissues such as your brain. Vigorous exercise can reduce blood sugar levels below 60 mg/dl (3.33 mmol/l), although it’s rarely a problem in non-diabetics.
The degree of glucose removal from the bloodstream by exercising muscles depends on how much muscle is working, and how hard. Vigorous exercise by several large muscles will remove more glucose. Compare a long rowing race to a slow stroll around in the neighborhood. The rower is strenuously using large muscles in the legs, arms, and back. The rower will pull much more glucose out of circulation. Of course, other metabolic processes are working to put more glucose into circulation as exercising muscles remove it. Carbohydrate consumption and diabetic medications are going to affect this balance one way or the other.
If you are at risk for hypoglycemia, check your blood sugar before your exercise session. If under 90 mg/dl (5.0 mmol/l), eat a meal or chew some glucose tablets to prevent exercise-induced hypoglycemia. Re-test your blood sugar 30–60 minutes later, before you exercise, to be sure it’s over 90 mg/dl (5.0 mmol/l). The peak effect of the glucose tablets will be 30–60 minutes later. If the exercise session is long or strenuous, you may need to chew glucose tablets every 15–30 minutes. If you don’t have glucose tablets, keep a carbohydrate source with you or nearby in case you develop hypoglycemia during exercise.
Re-check your blood sugar 30–60 minutes after exercise since it may tend to go too low.
If you are at risk of hypoglycemia and performing moderately vigorous or strenuous exercise, you may need to check your blood sugar every 15–30 minutes during exercise sessions until you have established a predictable pattern. Reduce the frequency once you’re convinced that hypoglycemia won’t occur. Return to frequent blood sugar checks when your diet or exercise routine changes.
These general guidelines don’t apply across the board to each and every diabetic. Our metabolisms are all different. The best way to see what effect diet and exercise will have on your glucose levels is to monitor them with your home glucose measuring device, especially if you are new to exercise or you work out vigorously. You can pause during your exercise routine and check a glucose level, particularly if you don’t feel well. Carbohydrate or calorie restriction combined with a moderately strenuous or vigorous exercise program may necessitate a 50 percent or more reduction in your insulin, sulfonylurea, or meglitinide. Or the dosage may need to be reduced only on days of heavy workouts. Again, enlist the help of your personal physician, dietitian, diabetes nurse educator, and home glucose monitor.
Finally, insulin users should be aware that insulin injected over muscles that are about to be exercised may get faster absorption into the bloodstream. Blood sugar may then fall rapidly and too low. For example, injecting into the thigh and then going for a run may cause a more pronounced insulin effect compared to injection into the abdomen or arm.
This issue is pretty technical and pertains to function of automatic, unconscious body functions controlled by nerves. These reflexes can be abnormal, particularly in someone who’s had diabetes for many years, and are called autonomic neuropathy. Take your heart rate, for example. It’s there all the time, you don’t have to think about it. If you run to catch a bus or climb two flights of stairs, your heart rate increases automatically to supply more blood to exercising muscles. If that automatic reflex doesn’t work properly, exercise is more dangerous, possibly leading to passing out, dizziness, and poor exercise tolerance. Other automatic nerve systems control our body temperature regulation (exercise may overheat you), stomach emptying (your blood sugar may go too low), and blood pressure (it could drop too low). Only your doctor can tell for sure if you have autonomic neuropathy.
I’ve run out of time today. For ideas, scan some of the articles under the Exercise category in the far right panel. FYI, here’s what I’m doing, but it’s not a good place for rank beginners to start. If you want to being resistance training, strongly consider some sessions with a personal trainer.
One of the key points of the essay for me is that exercise isn’t supposed to be fun. Ken wrote, “Do not try to make exercise enjoyable.” Getting your teeth cleaned or car’s oil changed isn’t supposed to be fun, either.
Once I got that through my thick skull, it made it easier for me to slog through my twice weekly workouts. Another excerpt:
We accept that both exercise and recreation are important in the overall scheme of fitness, and they overlap to a great degree. But to reap maximum benefits of both or either they must first be well-defined and then be segregated in practice.
Weight Maven Beth Mazur found evidence in favor of the fewer days, at least in post-menopausal women.
I don’t like to exercise. Sometimes I find excuses to avoid even my twice weekly 40-minute workouts. I do enjoy hiking; I even hiked to the bottom of the Grand Canyon and back out last May. But that’s not exercise, it’s more recreation.
You may well have good reasons to exercise every day. Maybe you’re a competitive athlete or enjoy exercise. If you just want the health benefits of exercise, I’m increasingly convinced that twice a week is enough.
…according to an article in MedPageToday. For unknown reasons, diabetics are less likely than average to get prostate cancer, but they still do.
In a prospective study, white men suspected of prostate cancer and scheduled for biopsy were less likely to have the disease if they were at least moderately active, according to Lionel Bañez, MD, of the Durham Veterans Affairs Medical Center in Durham N.C., and colleagues.
If they did have cancer, they were significantly less likely to have high-grade disease if they had been working out regularly, Bañez and colleagues reported online in Cancer.
Another way to reduce your risk of prostate cancer is to follow the Mediterranean diet. Other cancers reduced by the Mediterranean diet are breast, colorectal, and uterus.
Compared to a regular continuous walking program, interval walking is superior for improving physical fitness, blood sugar control, and body composition (body mass and fatness), according to new research reported in Diabetes Care.
Study participants were type 2 diabetics. Training groups were prescribed five sessions per week (60 min/session) and were monitored with an accelerometer and a heart-rate monitor. Continuous walkers performed all training at moderate intensity, whereas interval walkers alternated 3-min repetitions at low and high intensity. Before and after the 4-month intervention, the following variables were measured: body composition, VO2max, and glycemic control (fasting glucose, hemoglobin A1C, oral glucose tolerance test, and continuous glucose monitoring).
I haven’t read the full report yet, but expect that the interval walkers walked as fast as they could for three minutes (4 mph?) then slowed down to a comfortable stroll (1–2 mph?) for three minutes, alternating thusly for 60 minutes.
This should easily do-able for nearly all type 2 diabetics. The reported results are consistent with other studies of more vigorous and intimidating interval training. The only caveat is that it was a small pilot study that may or may not be reproducible.
I’m a minimalist when it comes to exercise. A really small, really intense dose is all that is needed for the vast majority of people to manifest all of the health benefits that exercise can provide. This does not mean that you can then get away with bed rest in the face of this concentrated dose of exercise, I’m not saying that at all. I’m saying that if a person is living a fairly “normal” life with a decent amount of non-exercise activity built into their day, not a lot of “exercise” is needed above that to maximize health markers.
I was planning to review for you an article, Resistance Training to Momentary Muscular Failure Improves Cardiovascular Fitness in Humans: A review of acute physiological responses and chronic physiological adaptations. It’s by James Steele, et al, in the Journal of Exercise Physiology (Vol. 15, No. 3, June 2012).
But it’s too technical for most of my readers. Heck, it’s too technical for me! Too much cell biology and cell metabolism. You’re dismissed now.
I’m just going to pull out a few pearls from the article that are important to me. I ran across this in my quest for efficient exercise. By efficient, I mean minimal time involved yet still effective.
The authors question the widespread assumption that aerobic and endurance training are both necessary for development of cardiovascular fitness. Like Dr. Doug McGuff, they wonder if resistance training alone is adequate for the development of cardiovascular fitness. Their paper is a review of the scientific literature. The authors say the literature is hampered by an inappropriate definition and control of resistance training intensity. The only accurate measure of intensity, in their view, is when the exerciser reaches maximal effort or momentary muscular failure.
The authors, by the way, define cardiovascular fitness in terms of maximum oxygen consumption, economy of movement, and lactate threshold.
“It would appear that the most important variable with regards to producing improvement in cardiovascular fitness via resistance training is intensity [i.e., to muscle failure].”
The key to improving cardiovascular fitness with resistance training is high intensity. These workouts are not what you’d call fun.
From a molecular viewpoint, “the adenosine monophosphate–activated protein kinase pathway (AMPK) is held as the key instigator of endurance adaptations in skeletal muscle. Contrastingly, the mammalian target of rapamycin pathway (mTOR) induces a cascade of events leading to increased muscle protein synthesis (i.e.,[muscle] hypertrophy).” Some studies suggest AMPK is an acute inhibitor of mTOR activation. Others indicate that “resistance training to failure should result in activation of AMPK through these processes, as well as the subsequent delayed activation of mTOR, which presents a molecular mechanism by which resistance training can produce improvement in cardiovascular fitness, strength, and hypertrophy.”
You’re not still with me, are you?
“… the acute metabolic and molecular responses to resistance training performed to failure appear not to differ from traditional endurance or aerobic training when intensity is appropriately controlled.”
Chronic resistance training to failure induces a reduction in type IIx muscle fiber phenotype and an increase in type I and IIa fibers. (Click for Wikipedia article on skeletal muscle fiber types.)
“It is very likely that people who are either untrained or not involved in organized sporting competition, but have the desire to improve their cardiovascular fitness may find value in resistance training performed to failure. In fact, this review suggests that resistance training to failure can produce cardiovascular fitness effects while simultaneously producing improvements in strength, power, and other health and fitness variables. This would present an efficient investment of time as the person would not have to perform several independent training programs for differing aspects of fitness.” [These statements may not apply to trained athletes.]
Before listing their 157 references, the authors note:
“It is beyond the scope of this review to suggest optimal means of employing resistance training (i.e., load, set volume, and/or frequency) in order to improve cardiovascular fitness since there are no published studies on this topic.”
In conclusion, if you’re going to do resistance training but not traditional aerobic/cardio exercise, you may not be missing out on any health benefits if you train with high intensity. And you’ll be done sooner.
PS: See Evidence-based resistance training recommendations by Fisher, Steele, et al.