What works? A large meta-analysis found that structured exercise training (in most studies, this consisted of 2-5 supervised sessions weekly for 12-16 weeks) led to a decrease in HbA1c (-0.67; 95% CI, -0.84 to -0.49). When the structured exercise was aerobic, HbA1c declined by 0.73 (95% CI, -1.06 to -0.40); when it was resistance training, HbA1c fell by 0.57 (95% CI, -1.14 to -0.01).21 Simply advising a patient to be physically active—without involvement in both the planning and supervision—led to statistically significant reductions in HbA1c only when the advice was combined with dietary recommendations. Giving patients both exercise advice and dietary recommendations led to an HbA1c reduction of 0.58 (95% CI, -0.74 to -0.43).21
The duration of the structured exercise mattered, too, of course, with those who exercised more than 150 minutes per week achieving a larger reduction in HbA1c than those who exercised 150 minutes or less (-0.89; 95% CI, -1.26 to -0.50 vs -0.36; 95% CI, -0.50 to -0.23). Higher intensity activity did not improve glycemic For patients with type 2 diabetes, higher intensity activity does not appear to lead to greater improvement in glycemic control compared with moderate intensity activity. control any more than moderate intensity exercise.21
Mind-body stress relievers
The National Health Interview Survey (NHIS) estimated that in 2007 (the most recent survey that addressed mind-body modalities), 19% of US adults used at least one mind-body modality in the previous 12 months.22 Modalities included in the NHIS were biofeedback and yoga, body interventions best studied for diabetes management. Here’s what the evidence shows:
Biofeedback. In a small RCT (N=30 patients with T2DM) comparing biofeedback-assisted relaxation training (10 weekly 45-minute sessions) with education alone, the treatment group had significant improvement in HbA1c levels (which went from 7.4% to 6.8%) and in average blood glucose values that persisted at 3-month follow-up.23
Biofeedback can also produce clinically significant toe temperature elevations. In patients with T2DM, volitional warming has been associated with increased circulation, improvement or elimination of intermittent claudication pain, more rapid healing of diabetic ulcers, and improved functional status.24
Yoga. Two systematic reviews concluded that yoga is likely to benefit patients with T2DM, leading to lower blood sugar, LDL-C levels, triglycerides, body weight, waist-to hip ratio, and HbA1c, and higher HDL-C.25,26 Additionally, yoga appears to have a beneficial effect on the blood pressure, heart rate, oxidative stress, sympathetic activation, catecholamine levels, coronary stenosis, coagulation profiles, and pulmonary function of patients with T2DM, and is associated with reductions in the amount of medication needed and in psychosocial risk factors. (Because of the heterogeneous nature of the studies reviewed, however, no statistical analyses were reported.)
A third systematic review, which included only 5 studies, found that yoga yielded a short-term improvement in FBG and lipids, but no statistically significant improvement in long-term outcomes of body mass index, body weight, or HbA1c.27 All 5 studies noted that there were methodological problems and uncertainty about the generalizability of the findings to Western culture.
Meditation. The regular practice of transcendental meditation (TM) is associated with a reduction of catecholamine levels, a study comparing meditators with a control group found.28 A study examining the relationship between depression and diabetes found compelling evidence of an association between mental stress and hypothalamic-pituitary-adrenal axis hyperactivity,29and another comparing meditators with controls found the regular practice of TM to be associated with a reduction in catecholamine levels.30 As increased catecholamine levels affect glucose transport and insulin resistance, this finding suggests that reducing stress levels through meditation might lead to improved glycemic control. Transcendental meditation has been found to reduce mean arterial pressure, insulin resistance, and insulin levels.
One RCT comparing diabetes education alone with education plus stress management (progressive muscle relaxation, deep breathing, and mental imagery) found that HbA1c levels decreased by 0.5 in the latter group at one year.31In a single blinded randomized study, the TM group had a statistically significant reduction in mean arterial pressure, insulin resistance, and insulin levels compared with those who received diabetes education alone.32
Qigong. The effectiveness of Qigong systems such as Tai Chi—which integrate physical postures, breathing techniques, and focused attention—is difficult to determine because of methodological challenges in design and variability in practice. Authors of a systematic review of Tai Chi and diabetes found only 2 RCTs and 3 nonrandomized clinical trials and concluded that there was no convincing evidence that the practice aids in glucose control.33 Two other systematic reviews of Qigong for T2DM reported some improvement in glucose control, but limited study quality prevented definite
conclusions.34,35
When to consider "manual medicine"