In other words, masks make it more difficult to breathe.
Shocking discovery, I know.
Physio-metabolic and clinical consequences of wearing face masks--Systematic review with meta-analysis and comprehensive evaluation
...
Background: As face masks became mandatory in most countries during the COVID-19 pandemic, adverse effects require substantiated investigation.
Methods: A systematic review of 2,168 studies on adverse medical mask effects yielded 54 publications for synthesis and 37 studies for meta-analysis (on n = 8,641, m = 2,482, f = 6,159, age = 34.8 12.5). The median trial duration was only 18 min (IQR = 50) for our comprehensive evaluation of mask induced physio-metabolic and clinical outcomes.
Results: We found significant effects in both medical surgical and N95 masks, with a greater impact of the second. These effects included decreased SpO2 (overall Standard Mean Difference, SMD = −0.24, 95% CI = −0.38 to −0.11, p < 0.001)...
SpO2 is blood oxygen level. Actually it apparently means "saturation of peripheral oxygen," which I take to mean that it's not a direct measure of oxygen in your blood, but a proxy measure for that, as people usually get their Pulse Oximetry taken via that thing that clips on to your index finger and reads your oxygen level through your skin. I'm guessing it's the skin that is the "peripheral" being analyzed for oxygen.
...and minute ventilation (SMD = −0.72, 95% CI = −0.99 to −0.46, p < 0.001), simultaneous increased in blood-CO2 (SMD = +0.64, 95% CI = 0.31--0.96, p < 0.001), heart rate (N95: SMD = +0.22, 95% CI = 0.03--0.41, p = 0.02), systolic blood pressure (surgical: SMD = +0.21, 95% CI = 0.03--0.39, p = 0.02), skin temperature (overall SMD = +0.80 95% CI = 0.23--1.38, p = 0.006) and humidity (SMD +2.24, 95% CI = 1.32--3.17, p < 0.001).
Here are some bad effects:
Effects on exertion (overall SMD = +0.9, surgical = +0.63, N95 = +1.19), discomfort (SMD = +1.16), dyspnoea (SMD = +1.46), heat (SMD = +0.70), and humidity (SMD = +0.9) were significant in n = 373 with a robust relationship to mask wearing (p < 0.006 to p < 0.001). Pooled symptom prevalence (n = 8,12
was significant for: headache (62%, p < 0.001), acne (38%, p < 0.001), skin irritation (36%, p < 0.001), dyspnoea (33%, p < 0.001), heat (26%, p < 0.001), itching (26%, p < 0.001), voice disorder (23%, p < 0.03), and dizziness (5%, p = 0.01).
Here's what all that means:
Discussion: Masks interfered with O2-uptake and CO2-release and compromised respiratory compensation. Though evaluated wearing durations are shorter than daily/prolonged use, outcomes independently validate mask-induced exhaustion-syndrome (MIES) and down-stream physio-metabolic disfunctions. MIES can have long-term clinical consequences, especially for vulnerable groups.
Oh my:
So far, several mask related symptoms may have been misinterpreted as long COVID-19 symptoms. In any case, the possible MIES contrasts with the WHO definition of health.
The conclusion? The downside of masks, combined with the complete lack of benefit for wearing them, means they shouldn't be worn, and certainly not mandated by government.
Conclusion: Face mask side-effects must be assessed (risk-benefit) against the available evidence of their effectiveness against viral transmissions. In the absence of strong empirical evidence of effectiveness, mask wearing should not be mandated let alone enforced by law.
Meanwhile, another study demonstrates that masks failed to control covid spread even in the venue where proper mask wearing and compliance would be at its highest: even in hospitals, masking failed.
Were masks in hospitals a waste of time? Hated NHS policy made 'no difference' to Covid infection rates, study finds
Experts at St George's Hospital found masks made 'no discernable difference'
The infection rate remained unchanged even when the mandate was removed
By Emily Stearn, Health Reporter For Mailonline
Masks made 'no discernible difference' to Covid transmission rates in hospitals, new research suggests.
Infection rates didn't soar when mask mandates were removed in NHS facilities during the middle of an Omicron surge.
Experts today said the findings did not mean face coverings are 'worthless'.
"Experts" are only expert in refusing to admit error, ever, even in the face of overwhelming evidence.
But they called for 'rational and proportionate' masking policies in hospitals during future Covid flare-ups because the benefits are 'at best, modest'.
Researchers found removing the mask policy in phase two did not produce a 'statistically significant change' in the hospital acquired Covid infection rate. Equally, they 'did not observe a delayed effect' in the Covid infection rate once the policy was removed, the study added.
This was despite a dearth of rigorous trials into their effectiveness.