Table 3.

Microbial changes observed in the included studies due to/associated with exercise/physical activity (adapted from [72]).

Phylum	Family	Genus	Physiological Effects/Associations Previously Detected
Actinobacteria ↑ [68]	Eggerthellaceae	Adlercreutzia ↓ [66]	Higher abundance in patients with back pain and positively correlated with BMI and inflammation [73]
	Bifidobacteriaceae	Bifidobacterium ↑ [67] ↑ [61]	Inhibit pathogens [74] Modulation of intestinal and systemic immune responses [74] Vitamin production [75] ↓ Inflammation [76], ↓ LPS [77]
Firmicutes ↓ [64]	Erysipelotrichaceae	Coprobacillus ↓ [66]	Positive correlation with frailty and associated with biological ageing [78]
	Ruminococcaceae	Ruminococcus ↑ [67]	Degrade and convert complex polysaccharides into a variety of nutrientsButyrate producers This genus has been associated with depression in some studies, although some species have anti-depressive effects [79]
		Faecalibacterium ↑ [65]	↓ Inflammation [80,81] Butyrate production [82] Protect against colon cancer [83]
		Oscillospira ↑ [63] ↑ [61]	Negatively associated with metabolic disturbances [84] Associated with leanness and ↓BMI [84,85]
	Clostridiaceae ↑ [68]	Clostridioides XI ↑ [67]	Increased in autistic children [86]
	Peptostreptococcaceae	Clostridioides ↓ [63] (C. difficile) ↓ [64]	Genus with several well-known pathogens (e.g. C. difficile) ↑ Inflammation [87] Alteration of gut microbiota composition [87]
	Lachnospiraceae ↑ [64,67]	Roseburia ↑ [64]	SCFAs production [88] Anti-inflammatory effects Abundance decreases concomitantly with muscle mass and dysfunction [89]
		Anaerostipes ↑ [61]	Production of acetate and butyrate [90] Beneficial role on renal function [91]
		Oribacterium ↓ [61]	Higher proportions were found in obese subjects [92]
	Selenomonadaceae	Mitsuokella ↑ [64]	Butyrate production [93]
	Streptococcaceae	Streptococcus ↓ [67]	Involved in the development of metabolic disorders, diabetes and colon cancer. Increases inflammation [94]
Bacteroidetes	Bacteroidaceae ↑ [68] ↓ [64]		Negatively correlated with body weight and fasted plasma insulin [95]. Members of this genus can be beneficial for the host and can be pathogenic as well, depending on several factors such as the taxonomical composition, geographic location or diet.
	Prevotellaceae	Prevotella ↑ [67] ↓ [61]	Beneficial for the GI tract and human health Propionate producersSome studies found that specific strains from the genus might be involved in inflammation [96]
		Paraprevotella ↑ [68]	Succinate and acetate producers [97] Reduced abundance in low functioning older adults [98] and sedentary women [99] Reduced abundance is associated with several diseases [100,101]
Proteobacteria	Oxalobactereaceae ↓ [68]		Increased abundance in cholangiocarcinoma patients [102] Increased abundance in patients with knee osteoarthritis [103]
	Sutterellaceae	Parasutterella ↓ [65]	Associated with IBS genesis and development [104] Associated with obesity, diabetes and fatty liver disease [65]
	Desulfovribionaceae	Bilophila ↓ [65]	Produces H2S which has cytotoxic effects on the gut membrane and inhibits butyrate production [105] Higher abundance induces systemic inflammation [106]
	Enterobacteriaceae	Escherichia ↓ [64]	This family has been associated with IBD and other GI tract diseases [107] LPS producers Pro-inflammatory
	Succinivibrionaceae	Succinivibrio ↓ [61]	Fiber degradation and typical in diets with high fibre and complex carbohydrates [108]
Verrucomicrobia	Akkermansiaceae	Akkermansia ↑ [64]	Decreased abundance was correlated with increased BMI [109] ↑ Insulin sensitivity and glucose tolerance [109] Reduces total cholesterol [110] Decreases fat mass [110]

We only included taxonomical changes that were statistically significant, ↑ Increased after or positively associated with exercise/physical activity, ↓ Decreased after or negatively associated with exercise/physical activity, METs—Metabolic syndrome; IBD (inflammatory bowel disease); LPS (lipopolysaccharide); UC (ulcerative colitis); GI (gastrointestinal); SCFAs (short-chain fatty acids); NAFDL (non-alcoholic fatty liver disease); TLR4 (toll-like receptor 4); BMI (body mass index); TG (triglycerides).