 Metformin is a commonly prescribed diabetes drug, but it is also popular among biohackers and life extensionists who take it for what they believe to be its longevity benefits. While this use is still being investigated, recent studies indicate that metformin may have some drawbacks, such as reducing the gains in respiratory performance brought on by exercise. Previous studies have shown that respiratory fitness, as defined by an increase in VO2 max, may play a role in preventing hyperglycemia and type 2 diabetes, although the associated weight loss is also likely to contribute. The researchers of this study sought to determine if metformin impairs gains in VO2 max the way it impairs muscle growth, as has been suggested by previous studies. This study focused on people most likely to be taking metformin, those with metabolic syndrome. A total of 72 overweight or obese people, with an average age of 53, were separated based on whether or not they were taking metformin. 63 of these people were able to complete 16 weeks of high-intensity interval training, which focuses on exercise sessions that maximize heart rate in order to increase cardiovascular and respiratory performance. Metabolic syndrome, respiration, and blood glucose were among the biomarkers assessed. However, this was not a placebo-controlled study, and the baseline characteristics of the two groups were different. Both groups were positively affected in every measurement of VO2 max, but the researchers' hypothesis was correct. The improvements brought on by the exercise in this respect were significantly blunted in the people taking metformin. While there was no significant difference in baseline measurements, the people who did not take metformin had better respiratory performance than those who did. Regardless of these results, it may be unwise to cease taking metformin if you are prescribed it by your doctor, but you should certainly ask your doctor any questions you may have. This study does illustrate a potential issue with metformin, especially for people who want to use it to augment their health rather than to treat an existing condition. Previous studies show that some cohorts do not experience reduced mortality, however, many people believe that metformin is still worth exploring as a longevity drug, which is why the team at Lifespan.io is working to support the long-awaited Targeting Aging with Metformin Trial or TAME Trial. I am very much looking forward to the results of this study, and it should answer many lingering questions that we currently have. When there is more to share, we'll have it for you here, so please subscribe so you don't miss out. I'm Ryan O'Shea and we'll see you next time on Lifespan News.