top of page

My Research

Research: Welcome

My main research interest builds up on the observation that night-shift work increases your risk to develop obesity, type 2 diabetes and cardiovascular diseases. When you think of night-shift work, there are 3 components to consider that are markedly different from our known daytime work schedules: We are exposed to light when our bodies are used to darkness, we consume food when our bodies are used to fast and we are physically active when our bodies are used to be resting lying horizontally in bed. These 3 factors share a common principle, so-called circadian misalignment (circadian for "approximately a day"). It means that the above-described features of night-shift work are not aligned with the natural course of the 24h day. And as our bodies consist of several biological clocks that are programmed to anticipate darkness, fasting and rest at night, our physiology and metabolism get out of balance. If such circadian misalignment persists over months of years as for example in repetitive night-shift work, we now know from large epidemiological studies that the development of metabolic diseases is much more likely than in non-shift working populations. Therefore, in my PhD, I studied these 3 different components of night-shift work and tried to better understand how the timing of light, food intake and exercise influence human metabolism. In this context, I particularly investigated the biological clock in skeletal muscle or in other words how the muscle knows what time it is outside of the body (read further in papers below).

During my Bachelor's and Master's programs, I studied the phenomenon of muscle cramping with a focus on the potential neural origin of cramps in the context of lumbar spine disorders like disc hernias. You would underestimate how many people are regularly suffering from leg cramps due to such lumbar disorders and have impaired sleep and thereby reduced life quality.  Unfortunately, there are not many helpful treatment options at hand and surgery does often aggravate cramping. We tested an electrical muscle stimulation protocol in people that are prone to cramp and saw promising long-lasting reductions in the frequency of leg cramps (read further in papers below).

I was also involved in clinical trials investigating blood-flow-restriction (BFR) training, which is a form of resistance training where you occlude the working muscles on purpose to interrupt blood and thereby oxygen supply to the muscle. By depriving the muscle of oxygen, you can create a metabolic milieu that is similar to working out with heavier weights while actually performing the exercise with very light weights. From an orthopedic perspective, BFR training is very interesting as you often encounter patients that are not able to perform heavy resistance training to build or maintain muscle due to a joint injury. It is also a promising so-called "prehabilitation" tool to prepare patients undergoing total hip or knee replacement surgery for the metabolic stress that occurs during surgery as surgeons need to similarly occlude the leg to avoid bleeding while connecting the new joint (read further in papers below).

Research: About
Research: About

Published Papers

Screenshot 2024-01-04 at 09.08.39.png
cell reports cover.JPG
Diabetologia header.PNG
Muscle clock paper header.PNG
Faseb paper header.PNG
BFR Frontiers header.PNG
NMES in lumbar header.PNG
NMES uncontrolled header.PNG
H-reflex EJAP header.PNG
IPC paper header 1.PNG
IPC paper header 2.PNG
Soft-tissue damage header.PNG
Orthopedic reviews header 3.PNG
Orthopedic reviews header 1.PNG
Orthopedic reviews header 2.PNG
Orthopedic reviews header 4.PNG
Preprint header.PNG

German articles

Harmsen JF & Doligkeit D (2020). Im Einklang mit dem Biorhythmus: Einunterschätztes Phänomen der individuellen Leistungsfähigkeit. In W. Leopold (Hrsg.), Schwimmen: Lernen und optimieren (Band 45, pp. 35-44): Deutsche Schwimmtrainer-Vereinigung.

Harmsen JF, Sistig A, Erb N, Behringer M (2018): Flüssigkeit und Elektrolyte oder Nervensystem – wo liegt die Ursache für Muskelkrämpfe? Deutsche Zeitschrift für Leistungssport, 48(1).

Research: Services
247 MUSCLE Schriftzug B.png
247 MUSCLE Schriftzug B.png
247 MUSCLE Schriftzug B.png
bottom of page