Diabetes increases the risk of cardiovascular disease,^[14] and people with diabetes commonly also have hypertension and dyslipidemia (abnormal blood lipid levels)^[15] — both of which increase the risk of cardiovascular disease. Chronic kidney disease develops in 20%–40% of people with diabetes, which is another risk factor for cardiovascular disease.^[16]

It’s estimated that up to 75% of people with type 2 diabetes have nonalcoholic fatty liver disease;^[17] both conditions are characterized by excessive fat in the liver and pancreas.^[18]

A meta-analysis^[10] suggests that people with diabetes and who are overweight or obese will have to lose over 5% of bodyweight on average before seeing an effect on hemoglobin A1c and cardiovascular risk markers. The authors of this meta-analysis admit that this can be a tough goal to achieve for some people, and often requires a mix of caloric restriction, healthy eating, physical activity, and regular visits to the doctor.

Lifting weights, or resistance training, has numerous benefits to the muscles and skeleton that are uniquely attributed to this form of training.

There are some cognitive benefits associated with exercise in general, but this FAQ entry will be more focused on what resistance training can give that other forms of exercise cannot.

Resistance training?

Resistance training is a form of training where the muscles and skeleton are pit against a large force, either induced by external resistance (lifting weights) or by gravity (maximal jumping or sprinting). Resistance training tends to be focused on power, and tends to be anaerobic (intense) in nature.

Anything with maximal exertions can be considered resistance training. Things like Tennis and racquetball show some benefits as well due to some strides being full exertion, but weightlifting tends to have the most dramatic effects.

Benefits to Muscles

Most notably weight lifting, but all forms of resistance training, can increase muscle mass.

This can reduce the occurrence of sarcopenia (the age-related decline in muscle mass not associated with pro-inflammatory cytokines)^[19] when elderly,^[20][21] although all activity can reduce rates of sarcopenia, resistance training seems most effective.^[22][23]

Benefits to Bone

Exercise in general tends to be associated with better bone mineral density and/or bone width in athletes when compared to a non-athletic control group.^[24][25][26] Greater bone health and an exercise regimen are inversely associated with falls in the elderly, which suggests that exercise is a good preventative measure.^[27][28][29]

It might also slightly protect against further reductions in bone mineral density in those already diagnosed with osteoporosis or osteopenia,^[30] although in general activity is encouraged.^[31]

In older age, those who practice Sprinting have been shown to have better bone density and size relative to jogging and walking activities.^[32] Although beneficial bone adaptations seem to be better in the young, they can still occur even if one starts a physical exercise program later in life.^[33]

It should be noted that swimming does not tend to increase bone density or mass, as the person is suspended in a pool of water rather than actively forcing power against gravity. It may increase bone health slighty in some persons, but is much less reliable than other forms of exercise.^[31][34][35]

Health Promoting effects

Involvement in exercise for at least 150 minutes a week in associated with a reduced risk of diabetes in men, with a protective effect existing for both aerobic exercise and weight training with persons participating in both having least risk.^[36]

C-reactive protein (CRP) is a marker of systemic inflammation. Adiponectin is a hormone from fat that protects against insulin resistance and atherosclerosis. An association seems to exist between higher CRP levels and an increased risk^[11] of diabetes by roughly 26% for each log mg/L increase in CRP. For each log μg/mL increase in adiponectin, there’s a 28% decrease^[12] in diabetes risk. However, it should be noted that this is a correlation, and not causation. The specifics of the relationship between diabetes and inflammation are still being teased out. So it’s not a good assumption to think that anything that lowers CRP or raises adiponectin must lower risk of diabetes. In fact, some researchers^[13] have argued that high CRP and inflammation may in fact be an effect, and not a cause, of insulin resistance. The case is not yet closed on the matter.

What is insulin sensitivity?

Definitions

Insulin sensitivity is a general phenomena in the body, and can be measured a few ways through studies.

The pancreas (an organ that regulates blood sugar) secretes insulin in response to high blood sugar, and cells (like muscle or fat cells) can absorb blood sugar when stimulated by insulin.

Insulin sensitivity is the relationship between how much insulin needs to be produced in order to deposit a certain amount of glucose. You are insulin sensitive if a small amount of insulin needs to be secreted to deposit a certain amount of glucose, and insulin resistant if a lot of insulin needs to be secreted to deposit the same amount of glucose.

Insulin sensitivity is seen as good as the opposite, insulin resistance, is a major risk factor for the development of Type II diabetes.

Types of Insulin Sensitivity

There are three main types of insulin sensitivity; peripheral insulin sensitivity, hepatic insulin sensitivity, and pancreatic insulin sensitivity.

Peripheral insulin sensitivity is how readily body cells in your periphery tissue, such as muscle and fat, can absorb glucose; either on their own (muscle can absorb glucose when contracted) or when insulin stimulates them. It is the most well-known form of insulin resistance.

Hepatic insulin sensitivity is related to the process of gluconeogenesis, the production of new blood sugar. Usually inflammatory factors prevent insulin from acting in the liver via inducing insulin resistance, and insulin's actions are unable to tell the liver to 'stop' producing glucose.^[37][38]

Pancreatic insulin sensitivity is the functioning of the cells that secrete insulin, the beta-cells. If these are damaged or cannot function, insulin resistance can develop. This is more of a concern in disease states like Type I diabetes (insulin insufficiency)^[39][40] or Cystic Fibrosis (where the function in physically hindered).^[41]

Insulin sensitivity is how effective the body is as using insulin to reduce elevated blood glucose levels, with a greater efficacy being more 'sensitivity' and poorer efficacy being more 'resistant'. When the body becomes too poor at using insulin to reduce blood glucose levels, type II diabetes ensues

Lifestyle

Non-modifiable factors

It seems that insulin sensitivity is negatively associated with age^[42] although these may be related more to lifestyle than to age per se.^[43] The ability to reverse insulin resistance with exercise does not appear to be different between young and old.^[42] Exercise tends to be recommended to older individuals to improve glucose metabolism.^[44]

Modifiable factors

There is an association with obesity and insulin resistance, with insulin resistant individuals usually having more body fat. However, this also appears to be lifestyle related as increases in insulin sensitivity can occur without weight loss.^[45] Some studies do note more drastic benefits in insulin sensitization in obese individuals, which is probably due to worse baseline statistics.^[45]

Exercise

Aerobic Exercise (Ex. Jogging)

Aerobic exercise, or exercise that you can maintain for a prolonged period of time, seems to be able to acutely improve insulin resistance by increasing uptake of glucose into cells. It can increase insulin sensitivity immediately, as a session of 25-60 minutes (at 60-95% VO₂ max) for 3-5 days.^[46] Improvements can also be seen after a week of aerobic training, when doing mostly 2 short sessions of 25 minutes of walking at 70% VO₂ max.^[47] Interestingly, the opposite is also true. Voluntary restriction of activity or a drastic increase in sedentary activity can reduce insulin sensitivity in as little as 2 weeks.^[48]

Over the long term, aerboic exercise done routinely can preseve beneficial changes in insulin sensitivity.^[49]

Insulin sensitivity as a result of exercise can occur independent of weight loss.^[45][50] This is not to say that aerobic exercise will not lead to weight loss, as it may.^[51] The function of weight loss seems to be a blend of activity and diet, whereas insulin sensitivity increases could occur without changes in the diet.

In regards to hepatic insulin resistance, it has been seen over time periods of 12 weeks light aerobic activity^[52][45] but studies lasting 1 week have sometimes noted no difference.^[47]

Anaerobic Exercise (Ex. Weightlifting)

Strength exercises (lifting weights usually) is also associated with increasing insulin sensitivity as well as increased muscle mass.^[53]

In persons with impaired glucose tolerance, more sets of an exercise tend to be more effective than single sets and higher intensities better than moderate.^[54]

The general idea of exercise is that you want to have lean (muscle) mass, and you want it to contract somewhat regularly so it can take up glucose. The more properly functioning muscle mass one has, the better peripheral insulin sensitivity is

Supplementation

Supplements may be either supplements that directly act upon cells to induce insulin sensitizing effects (like resveratrol or carnitine) or may inhibit or otherwise delay carbohydrate uptake (like green tea catechins and perhaps chlorogenic acid)

Using some of these compounds in conjunction with diet/exercise techniques conducive to regaining insulin sensitivity would be advisable.