Insulin resistance is often associated with a lack of movement or being overweight. In reality it is a disorder that appears in many different life scenarios – including in people who are slim, who train or who live intensely. They have one thing in common: the muscles stop taking up glucose from the blood effectively, and the body loses its ability to respond smoothly to insulin.
Updated: 14 September 2026
In recent years, more and more attention has been paid to methods that can support improved insulin sensitivity outside classic training. Electrical muscle stimulation (EMS), used in both sport and rehabilitation, is among the tools that act withinthe most basic mechanism of glucose regulation– the contractile work of the muscle fibres.
This article explains how that mechanism works, why the recruitment of fast fibres is crucial here and why EMS can be particularly helpful for groups that, for various reasons, find it hard to achieve intense muscle recruitment in classic training.
Contents:
Muscles and glucose – the foundation everything starts from
Most of the glucose circulating in the blood ends up in the skeletal muscles. They are the body's largest and most dynamic glucose „store”. For a muscle to take up glucose, GLUT4 transporters must appear on its surface – specialised proteins acting like gates through which glucose can enter the cell.
GLUT4 is activated in two ways:
- under the influence of insulin,
- under the influence of muscle contraction.
The second of these mechanisms is independent of the first. This means that even if a cell is less sensitive to insulin, once it is forced to work it can still take up glucose effectively. This pathway is well described in the literature and is one of the foundations on which the influence of physical activity, and of electrostimulation, on metabolism rests.
Why electrostimulation works as an intense contraction stimulus
Electrostimulation triggers a muscle fibre contraction through direct depolarisation of the motor nerve. It does not imitate movement, it forces it. From the muscle cell's point of view it makes no difference whether the contraction was caused by a weight, a sprint or an electrical impulse: the glucose-uptake mechanisms are the same.
What sets EMS apart is the way fibres are recruited. Natural movement follows Henneman's principle: slow-twitch fibres (type I) are activated first, and only at high intensity do the fast fibres (type IIa, IIx) join in. Many people are unable to reach the threshold at which those fast fibres are fully engaged.
With electrostimulation, the order is different. The electrical impulse skips the stage of gradually increasing intensity andalso recruits the fast fibres right from the start of the work. These are the fibres with the greatest capacity to use glucose, particularly during repeated high-frequency contractions.
This is precisely why electrostimulation can be an effective metabolic stimulus even for people who, in classic training, are unable to achieve full activation of the fast motor units.
Fast fibres – why activating them matters in insulin resistance
Type II and IIx fibres are characterised by:
- a high capacity to take up glucose,
- high working dynamics,
- rapid use of energy resources,
- a significant share in overall muscle metabolism,
- a tendency to lose mass in the absence of stimuli.
They are the ones responsible for the largest percentage of glucose consumption during intense effort.
If they are not stimulated regularly, the body loses part of its capacity to use glucose, and insulin starts to work less effectively.
A large proportion of people with insulin resistance – regardless of body weight – do not reach that activation threshold during ordinary movement. These may be:
- obese people,
- slim people with chronic stress and poor sleep quality,
- people who live intensely, train a lot but recover poorly,
- women with circadian rhythm disorders,
- people after injuries,
- people starting activity from zero.
In each of these scenarios, electrostimulation can act as the missing stimulus that restores the fast fibres to the role they ought to play in metabolism.
The advantage of EMS: intense activation at a lower recovery cost
High-intensity training, which recruits fast fibres naturally, can be hard to tolerate – particularly in people with dysregulated glucose metabolism. Glucose swings, high cortisol and disturbed sleep mean that intense effort can leave behind a state of fatigue lasting many hours, straining the nervous system and reducing the capacity to recover.
Electrostimulation makes it possible to deliver a strong contraction stimulus:
- in less time,
- without heavy loading of the joints,
- with less activation of the sympathetic nervous system,
- with less risk of overloading the musculofascial structures,
- under conditions that are more accessible for many people.
This allows a person with insulin resistance to benefit from the effect that matters most, the activation of glucose-hungry muscle fibres, without having to perform intense training that their body might tolerate poorly.
What that means in practice
Electrostimulation does not replace a healthy diet, it is not a medical therapy and it is no alternative to movement as such. As a tool supporting muscle work, however, it can improve glucose utilisation by stimulating fibres that in many cases are not activated often enough or intensely enough.
As a result, regular EMS sessions, combined with good sleep hygiene and balanced nutrition, may help to:
- improve glucose transport into the muscles,
- increase tissue sensitivity to insulin,
- support the rebuilding of muscle mass,
- reduce overload-related metabolic stress.
This approach is consistent with current physiological knowledge and provides a solid foundation for building education around metabolism and modern training methods.
References
1.Sanchez, M. J., et al. (2023).Effects of neuromuscular electrical stimulation on glycemic control: A systematic review and meta-analysis.Frontiers in Endocrinology.
2.van Buuren, F., et al. (2015).Electrical myostimulation improves glucose metabolism in type 2 diabetes: A clinical study.
3.Galván, M. J., et al. (2022).Four weeks of neuromuscular electrical stimulation enhances glucose tolerance and muscular metabolic function.
4.Wirtz, N., et al. (2015).Acute metabolic and hormonal responses to strength training with and without superimposed electromyostimulation.
5.Aldayel, A., et al. (2010).Hormonal and metabolic responses to neuromuscular electrical stimulation: A comparison between stimulation modalities.Journal of Applied Physiology.
6.Guretzki, E., et al. (2024).Whole-body electromyostimulation and its effects on metabolic risk markers: A systematic review.
7.Soedirdjo, S. D. H., et al. (2023).Sex hormone–related differences in muscle activation across the menstrual cycle.
