Muscle Haemodynamics and Oxygen Saturation during Exercise and Recovery in Chronic Fatigue Syndrome Patients, 2018, Singh et al.

[SNT Gatchaman]

Muscle Haemodynamics and Oxygen Saturation during Exercise and Recovery in Chronic Fatigue Syndrome Patients
Jyotpal Singh, Andy D. Roberts, Michael F. Harrison, Nina H. Leavins, James C. Croll, Bharath Krishnan, Patrick Neary

INTRODUCTION
Controversy exists in the literature whether or not muscle metabolism is altered in chronic fatigue syndrome (CFS) patients.

PURPOSE
To examine the effects of incremental exercise to volitional exhaustion and recovery on muscle haemodynamics and oxygen saturation in CFS patients.We hypothesized that fatiguing exercise would demonstrate differences in comparison to healthy control (CON) subjects.

METHODS
Six CFS patients and eight physically similar CON subjects performed an incremental cycle ergometer test. The warm-up workload began at 30W for 3 min, followed by an increase to 60W for 2 min, and then 25W increments every 2 min thereafter. Total hemoglobin (tHb; μM), deoxyhemoglobin (HHb; μM), and tissue oxygenation index (TOI; %) were monitored during exercise and passive recovery (2 min) from the right vastus lateralis muscle using spatially resolved nearinfrared spectroscopy (NIRS).

RESULTS
ANCOVA from the NIRS data revealed that the CFS group had a significantly lower TOI% (58.9 ± 1.8% vs. 64.0 ± 1.2%) throughout exercise, and longer recovery time (t½; Tau) after exercise (τ = 29.5s vs. 17.7s; P<0.05). Kinetics for tHb (τ = 18.5s vs. 39.7s), and HHb (τ = 18.7s vs. 31.7s), was significantly reduced after passive recovery in the CFS patients vs. CON, respectively.

CONCLUSIONS
The reduced muscle TOI% during and after exercise in the CFS patients suggests that peripheral muscle metabolism was altered and different from CON subjects. Furthermore, the longer recovery kinetics (τ), in tHb and HHb during recovery suggests altered metabolic and hemodynamic changes in CFS, and may indicate a peripheral autonomic imbalance.

Link | PDF (Journal of Chronic Diseases and Management) [Open Access]

 

[SNT Gatchaman]

2018 study which I don't think we have a thread for. Small numbers vs healthy controls. It looks like they used Fukuda, which was their first reference, later stating in methods —

Six physician-referred female CFS patients and eight control (CON) subjects of similar body composition provided written informed consent after ethical review by a University committee was approved. The inclusion criteria for the CFS group were in accordance with the Center for Disease Control and confirmed CFS by the referring rheumatologist, thus, allowing for control of other comorbidity illnesses (i.e., fibromyalgia) as this has demonstrated an altered cognitive performance and physiological response in comparison with CFS-only subjects following exercise.

In terms of whether these were sedentary HCs —

Physical activity level (sessions per week > 1.5 metabolic equivalent) (CFS: <1; CON: <10)) were matched for control of possible influences.

That seems at least relatively sedentary even if we don't know the MET-mins/week. According to the governmental Australian Institute of Health and Welfare —

• Sedentary: Less than 600 MET-mins per week
• Low: 600 – 2,399 MET-mins per week
• Moderate: 2,400 – 4,199 MET-mins per week
• High: Greater than 4,200 MET-mins per week

See also Sedentary Behavior Research Network SBRN – Terminology Consensus Project process and outcome (2017, International Journal of Behavioral Nutrition and Physical Activity)

The HCs also reported a non-zero fatigue score: "Fatigue Severity Scale (CFS: 59±5; CON: 27±15; p<0.05)"

 

[SNT Gatchaman]

A relatively recent study in ME/CFS patients is Muscle Haemodynamics and Oxygen Saturation during Exercise and Recovery in Chronic Fatigue Syndrome Patients (2018, Journal of Chronic Diseases and Management)

That shows differences to sedentary controls. TOI is tissue oxygenation index, another term for tissue saturation index (TSI) and muscle oxygen saturation (SmO2) all interchangeable terms used in the literature I believe.

This study was novel as it showed that skeletal muscle metabolism during exercise and resaturation kinetics during recovery was significantly lower in patients with CFS in comparison to normal healthy control participants. Using the time constant Tau (t; sec), we examined the kinetics of tHb and HHb, and resaturation of T0I%, and found that these muscle oxygenation variables were significantly blunted in the CFS patients when assessed using non-invasive NIRS. Furthermore, our research demonstrates that skeletal muscle oxygen kinetics using a simple method, i.e., recovery from exercise, can differentiate healthy from pathological states of function.

Where I think a wearable device like the Moxy Monitor could be useful is looking at what happens in the 24-48 hours after exercise. I think exercise studies to date have only looked at the exercise and immediate post-exercise recovery phase.

Also we can look more easily at moderate and severe patients who could not do an exercise challenge.