Aerobic neuromuscular electrical stimulation--an emerging technology to improve haemoglobin A1c in type 2 diabetes mellitus: results of a pilot study

Abstract

Objectives: A new generation of neuromuscular electrical stimulation (NMES) devices can exercise aerobically at equivalent rates to voluntary exercise. Many with type 2 diabetes cannot or will not exercise sufficiently. The objective of this pilot investigation was to see (1) if it was an acceptable training modality for men with type 2 diabetes mellitus and (2) to assess effects on haemoglobin A1c levels.

Design, setting, participants and intervention: A case series of eight men with type 2 diabetes mellitus (aged 53±8; body mass index 32±5 5 kg/m(2)) trained with the NMES system for 1 h 6 times weekly for 8 weeks, unsupervised, at home. There were no other medication or lifestyle interventions. The aerobic NMES exercise system delivers a repeating set of four complex staggered pulses at high intensities (typically 100 mA+) through an array of eight thigh electrodes.

Outcome measures: The primary outcome measures were changes in haemoglobin A1c and the responses in a questionnaire on participants' perceptions of the system. Body mass and composition were also measured before and after the NMES intervention period.

Results: All participants could use the system at a level that left them breathless and sweaty and with a heart rate over 120 beats per minute. Haemoglobin A1c levels improved by 0.8±0.7% from 7.4±1.3% (mean ± SD) to 6.6±1.0% (p=0.01). All participants considered the system suitable for people with diabetes, would recommend it and would continue to use it twice a week 'to maintain improvements'.

Conclusions: These results suggest that aerobic NMES may be acceptable and have a beneficial effect on haemoglobin A1c of some men with diabetes. The treatment may be of particular benefit in those who will not or cannot do adequate amounts of voluntary exercise. A randomised control trial is required for conclusive efficacy data.

Conflict of interest statement

Competing interests: None.

Figures

Figure 1

Four large hydrogel electrodes are applied to the skin of each thigh using a neoprene wrap. The electrodes were pre-wired and mounted inside the wrap. The model's left leg is without the garment to illustrated electrode positioning.

Figure 2

Simplified diagram of pulse pattern. Each pulse is represented by a different colour. The current passes between different sets of electrodes within each pulse. The electrodes are described by their position, that is, RUQ—right upper quadriceps electrode, RUH—right upper hamstring, RLQ—right lower quadriceps, etc. See also Figure 1 for picture of electrode positions. The pattern has four pulses; within this pattern, the pulses are separated by either 40 or 5 ms. For aerobic effect, the pattern is repeated five times per second. Each pulse has a different function and is further subdivided into timeslots. Differing electrode combinations are active during separate timeslots of a given pulse, for example, pulse 1, in red, is shared between the upper and lower quadriceps of both legs. By defining the timeslots, the upper quadriceps ‘see’ both a higher current intensity and a longer pulse duration than the lower electrodes. (This is not shown.) The second pulse, in blue, has five timeslots, and it targets the muscle bulk of the right leg. The third pulse, in green, follows 5 ms later; it is similar to the second pulse except it targets the muscle bulk of the left leg. Forty millisecond later, the fourth pulse, in black, spreads current between the hamstring electrodes.