Is too much HIIT too much?

A recent study by the Swedish School of Sport and Health Sciences seems to indicate that too many consecutive HIIT (high interval intensity training) workouts might produce negative health results over time. (Click here to see the study: https://www.cell.com/cell-metabolism/fulltext/S1550-4131(21)00102-9) According to the study, "excessive training causes mitochondrial impairment and reduced glucose tolerance in healthy volunteers." These results are quite interesting but may require further investigation since this particular study was only 4 weeks in length and only had 11 participants. The results do, however, provide a good suggestion to vary your workouts. Add some strength training to your workouts to avoid too much HIIT.