Physical exercise indication
It is RECOMMENDED that physicians and other health care professionals encourage physical activity and exercise for T1DM individuals as part of their treatment
Summary of evidence
This recommendation is grounded on expert opinion. Health care professionals recognize their role in helping T1DM individuals incorporate physical activity into diabetes management and daily life, however, barriers to successfully integrate these activities are noted. It is important that health care professionals encourage regular participation of adults and children in different physical activity programs .
Cardiovascular risk assessment
It is RECOMMENDED that physicians must evaluate cardiovascular risk in all T1DM individuals, in accordance with SBD risk stratification table, before prescribing physical activity or exercise
Summary of evidence
Based on experts’ opinions, screening for cardiovascular diseases in not recommended for low or moderate intensity exercises when referring to asymptomatic T1DM individuals who do not fall into the high or very high-risk categories, since these individuals present a low Predictive Value [1, 17].
High or very high risk T1DM individuals who will begin exercising should be evaluated at least through resting electrocardiogram, and, when indicated, other tests may be performed .
Important note 2: High intensity exercises
Important note 3: Exercises and retinopathies
Important note 4: Peripheral neuropathies and exercise.
Individuals with peripheral neuropathy should be advised to wear appropriate footwear and to always perform foot self-examination before and after exercise. They may perform resisted physical exercises, such as weightlifting, if there are no ulcers on the feet .
It is RECOMMENDED that individuals with high or very high risk T1DM, who wish to begin exercise, be initially screened with electrocardiogram in resting position. Depending on individual analysis of each case, additional tests may be requested
A longitudinal cohort study by Soliman et al.  aimed to assess the association between the prevalence and incidence of electrocardiographic abnormalities and the development of cardiovascular diseases (CVDs) in T1DM individuals. The study involved 1,306 individuals (mean age 35.5 years ± 6.9 years; 47.7% women). During a mean follow-up of 19 years, 155 participants (11.9%) developed cardiovascular conditions. The study concluded that the presence of major ECG changes is associated with increased risk of CVD in T1DM. This indicates the importance of ECG screening in T1DM individuals in order to properly identify risk for CVD, especially before beginning an intensive exercise program.
It is RECOMMENDED that T1DM individuals perform at least 150 min per week of moderate or vigorous intensity aerobic exercise, with no more than two consecutive days resting, for improving fitness and BMI control
Summary of evidence
A meta-analysis of 14 randomized controlled studies that evaluated the effect of exercise training in T1DM individuals regarding HbA1c, BMI, and other anthropometric and biochemical parameters, presented no difference in HbA1c levels in adults after exercise. However, BMI was significantly lower [mean difference − 0.39 kg/m2(95% CI − 0.75 to − 0.02; p = 0.03; I2 = 0%)] .
The performance of moderate aerobic exercise is associated with lower cardiovascular mortality, and also decrease in all-cause mortality in T1DM and T2DM .
An observational study of T1DM adults suggests that higher amounts of physical activity led to lower cardiovascular mortality after an 11.4-year follow up in individuals with and without kidney disease .
Children with T1DM should engage in combined aerobic and resistance exercise at least three times per week, for more than 12 weeks, to reduce HbA1C levels .
Important note 5. Adjustment of insulin doses
In T1DM individuals, aerobic, resistance, or combined training in the same session MUST BE CONSIDERED for improving endothelial function, fitness, and glycemic control
Summary of evidence
In young and well-conditioned individuals, it should be considered the practice of at least 75 min of weekly high-intensity interval training (HIIT), caring not to remain more than two consecutive days without exercise . HIIT improves peak VO2 and arterial stiffness similarly to moderate intensity continuous training, with the advantage of enabling greater glycemic stability and lower hypoglycemia risk when compared to continuous training . In a nourished state, HIIT is a safe, effective, and time-flexible form of exercise for T1DM individuals [15, 21]. It is worth noting that the intensity assessment of aerobic exercise can be evaluated in different ways, by objective or subjective parameters .
The study by Boff et al. aimed to compare the effect of high intensity interval training (HIIT) with moderate intensity continuous training (MICT) on endothelial function, oxidative stress and fitness in T1DM individuals. Thirty-six T1DM individuals (mean age 23.5 ± 6 years) were randomized into three groups: HIIT, MICT and a no exercise group (CON). Exercise was performed on a cycle ergometer for 40 min, three times a week for eight weeks, with 50% to 85% of maximum heart rate (HRmax) in HIIT and 50% in MICT. Glycemic control was similar in all groups. In individuals with type 1 diabetes without microvascular complications, after eight weeks HIIT produced significant improvement in endothelial function and fitness compared to MICT with similar glycemic control .
Today, with the advance of technology, active video gaming (AVG) can be considered an alternative exercise to aerobic exercise. Gomes et al. , compared the effects of AVG and running on cardiovascular and pleasure responses in T1DM individuals. Vessel diameter (VD) and percentage of endothelial function (%EF) were greater in the AVG group, followed by running and resting, 30 min and after 24 h (VD-AVG: 39.6 ± 9.5, 48.8 ± 12.3 and 56.6 ± 13.9 mm; VD-running: 41.5 ± 9.9, 47.4 ± 10.1 and 46.4 ± 12.4 mm; % EF-AVG: 9.6 ± 8.5, 29.6 ± 17.1 and 45.4 ± 25.9%; % EF-run: 7.3 ± 9.4, 14.8 ± 14.1 and 26.8 ± 18.9%; p < 0.05). Enjoyment was also higher in the AVG compared to the running session (9.4 ± 0.7 vs. 7.7 ± 1.6; p < 0.05). AVG showed similar cardiovascular responses when compared to running, however, it also demonstrated improvements in endothelial function and pleasure levels.
In a study performed by Reddy et al. T1DM individuals used a resistance training protocol. In the study, ten adults with T1DM over 12 weeks were allocated to aerobic exercise, resistance exercise, and no exercise groups in an open, crossover study design. The resistance training protocol was 8 to 12 repetitions of five exercises for upper and lower limbs, with strength intensity between 60 to 80% of individuals one maximum repetition. The primary outcome was percentage of time in range (glucose > 3.9 mmol/L and ≤10 mmol/L) for the 24 h after each bout of exercise or rest during the control week. The group undergoing resistance training showed greater time on target 24 h after the intervention (70 vs. 56%; p = 0.013), reinforcing the benefits of resistance training for glycemic control in this population .
When compared to aerobic exercise, resistance exercise can increase blood glucose during its execution, determining a lower risk of hypoglycemia, both acutely and post-exercise. Anticipating resistance exercise in relation to aerobic training seems efficient to minimize the risk of hypoglycemia in individuals undergoing insulin therapy . Individualization of the exercise plan is critical for therapeutic success.
The combination of aerobic exercise (brisk walking, running, cycling, swimming) with resistance exercise (free weights, weight-training equipment, elastic bands, or using one's own body weight) and the progressive increase of volume, frequency, load, and intensity have proven effective for the health of individuals with diabetes, promoting a reduction in HbA1c (− 0.1 to − 1.1% in aerobic training, − 0.2 to − 1.6% in resistance training, and 0.1 to − 1.5% in combined training), among other benefits [5, 12, 19].
A systematic review with meta-analysis by Flores et al. . aimed to analyze the effects of physical training on neuromuscular parameters in T1DM individuals. Compared to aerobic training, strength training increased maximal strength (ES: 1.067; p < 0.001), as did combined training (ES: 0.943; p < 0.001).
It is RECOMMENDED that T1DM individuals, especially the elderly ones, perform exercises to improve balance and flexibility in order to develop a better range of motion, dynamic and static balance
Summary of evidence
Elderly individuals should prioritize balance and flexibility training. According to individual preferences, exercises such as yoga, tai chi chuan, and joint mobility are recommended for older adults with T1DM [1, 17].
Adults (50 years and older) with diabetes should exercise to maintain and/or improve balance two to three times a week, especially if the patient is diagnosed with peripheral neuropathy. Yoga and tai chi chuan can be included based on individual preferences to increase flexibility and balance .
In T1DM individuals, glucose monitoring is RECOMMENDED before, during, and after exercise to minimize blood glucose variability and risk of hypoglycemia, consider these suggestions also for people with type 2 diabetes who use insulin or sulfonylureas
Summary of evidence
Some precautions can prevent hypoglycemia during exercise and increase the safety of diabetics and those who use insulin, including informing supervisors/counselors and their exercise partners about their clinical condition; Obtaining easy and quick access to fast-absorbing carbohydrates; capillary blood glucose monitoring before, during and after exercise; paying attention to possible symptoms of hypoglycemia , consider these suggestions also for people with type 2 diabetes who use insulin or sulfonylureas.
Hypoglycemic events can occur during and after the exercise session. The increased risk of hypoglycemia may be related to improved insulin sensitivity. However, high-intensity exercise can increase blood glucose levels instead of reducing them, and speed sprints can be a strategy to prevent an imminent crisis of hypoglycemia . If pre-exercise blood glucose is elevated or if the effects of counterregulatory hormones replace those of circulating insulin, high-intensity exercise can raise blood glucose .
Pre-exercise glycemic values above 250 mg/dL need special management (see Table 4 for suggested management).
In T1DM individuals, continuous glucose monitoring (CGM), flash glucose monitoring based on transcutaneous placed glucose oxidase, by transcutaneous placement, CAN BE CONSIDERED during exercise
Summary of evidence
Technology has made it possible to observe more frequently the behavior of interstitial glucose during and after exercise, including at night, and in different sports. Such strategies can decrease the risk and fear of exercise-induced hypoglycemia by providing trends of glycemic variation to help users perform interventions to prevent hypoglycemia and hyperglycemia [30, 31].
Detachment of sensors on the skin, breakage of device filaments, and inability to calibrate may compromise their accuracy and lag-time (lag time in the balance between blood glucose and interstitial glucose values that occurs especially during exercise). The use of these sensors still does not make it possible to dispense with capillary blood glucose monitoring .
The use of arrow tables on flash monitors for blood glucose management during exercise in T1DM individuals MAY BE CONSIDERED (Table 4)
Summary of evidence
The direction of the glycemic excursions depends, to some extent, on the intensity and duration of the exercise type. Understandably, fear of hypoglycemia is one of the strongest barriers to incorporating exercise into daily life. Risk of hypoglycemia during and after exercise can be reduced when insulin-dose adjustments are made and/or additional carbohydrates are consumed .
The use of CGM in exercise studies has allowed the evaluation of trends, by means of arrows and post-exercise (especially nocturnal), for different exercise modalities in T1DM individuals. CGM provides information about late post-exercise responses to help T1DM individuals control their glucose, and is useful as a tool to teach T1DM individuals about exercise responses . Table 4, presents the exercise prescription according to the arrow’s direction.
Important note 6: CGMs precision
Exercise can affect accuracy of the available CGMs, suggesting the need to keep blood glucose in a "cautious" range, above what is generally recommended.
In addition to assessing blood glucose and considering pre-exercise trend arrows, it is important to assess circulating, active insulin to avoid hypoglycemia during or after exercise.
For T1DM individuals using continuous insulin infusion system (CSII), it MAY BE CONSIDERED to reduce the prandial bolus of the meal preceding exercise, reduce the basal infusion rate for a while, or even disconnect it temporarily 
Summary of evidence
T1DM individuals on continuous subcutaneous insulin infusion (CSII) can reduce the prandial bolus of preceding meal of the exercise, however, the activity must be performed early in the postprandial state (up to 90 min after administration of the prandial bolus). If exercise is not preceded by a meal, individuals may be instructed to disconnect the pump or set a temporary basal rate (50%-80% reduction) at least 90 min before starting exercise [33, 34].
During longer unusual and/or all-day activities (e.g., summer camps or sports clinics), after the activity, individuals may consider a 30% to 50% reduction in basal insulin, throughout the day and evening .
Important note 7: Insulin dose
Physical activity and exercise in type 2 diabetes mellitus
The decision to screen asymptomatic T2DM individuals in order to evaluate the presence of CVD before starting an exercise program will depend on the presence of risk stratifiers, presence of cardiovascular symptoms, and intensity of the exercise. Table 3 demonstrated the strategy suggested by the SBD for the indication of screening of cardiovascular disease in individuals with T2DM without known cardiovascular disease.
For individuals eligible for screening before begining exercises, the necessary evaluation tests must be individually determined. The resting electrocardiogram is considered a basic and essential test and should be ordered in all relevant cases. In relation to alternative, more complex, more expensive or more invasive tests, it should be evaluated according to clinical scenario.
For individuals with increased risk of developing T2DM or already in a pre-diabetic state, 150 min of moderate-intense aerobic exercise reduces the risk of developing type 2 diabetes. For individuals with T2DM, combined resistance exercise (at least 1 cycle of 10 to 15 repetitions of 5 or more exercises, two to three sessions per week, on non-consecutive days) and aerobic exercise (at least 150 min per week of moderate or equivalent high intensity, with no more than two consecutive days of no activity) promote significant reductions in HbA1c. Table 1 describes examples of suggested exercises. It is also recommended that adults, especially the elderly, perform physical exercises that improve balance, such as tai chi and yoga, two to three times a week [36, 37].