Browse evidence-based analysis of health-related claims and assertions
Women with kidney disease who are getting a new kidney tend to have bigger and less flexible heart chambers before the surgery than men, which might mean their hearts have been working harder for longer.
Descriptive
After a kidney transplant, men’s heart pumping ability improves more than women’s, even though women’s hearts were already pumping better to start with.
Correlational
After getting a new kidney, women’s hearts show more improvement in a specific heart measurement than men’s, even though women started with a larger heart size — suggesting their hearts recover differently based on sex.
After a kidney transplant, men’s hearts tend to shrink back to a healthier size more than women’s hearts do over six months—even though men’s hearts were bigger to begin with—suggesting that men and women’s hearts respond differently to the transplant.
Causal
Lifting weights through a shorter movement range can build muscle just as well as lifting through a full movement range — no difference in muscle growth.
Quantitative
If you're already eating enough protein, taking extra leucine won't help you build more muscle.
If you swap regular table salt for a salt substitute that has more potassium, it might lower your chance of having a stroke by about 14%.
After getting a new kidney, women’s hearts don’t shrink as much in size as men’s hearts do.
Taking creatine monohydrate won’t help trained rowers do more reps during weight training or maintain higher power during repeated rowing sprints.
If trained rowers do six weeks of intense rowing and weight training, they’ll get stronger, row faster, and lose fat or gain muscle—even if they don’t take creatine supplements.
Taking creatine powder while doing intense rowing and weight training won’t make you stronger, faster, or change your body composition any more than taking a sugar pill instead.
After lifting weights, your muscles make more of a protein called Cyclin D1 quickly — not by turning on new genes, but by using existing instructions more efficiently, which might help your muscles adapt and grow.
Mechanistic
Even after working out with weights for 8 weeks, your muscles still respond to a single workout the same way as they did at the start—your body doesn’t get better at signaling muscle growth after training for a while.
After working out with weights for 8 weeks, your body keeps its protein-making machines more active even when you're resting, as if it's always ready to build more proteins.
When you lift weights, your muscles make more of the tiny molecular machines that build proteins, which helps them grow bigger.
If a young, healthy man lifts weights for 8 weeks, his muscles will likely get bigger—by about 6%, give or take a little.
If you're over 60 and lifting weights, doing it more than twice a week probably won't make you any stronger or give you bigger muscles than doing it just twice a week.
For people over 60, adding one extra day of weight training each week might help them get a little stronger, but it won’t make their muscles noticeably bigger.
When you exercise, your muscles make a protein called TSC1 stick to the internal skeleton of the cell, and at the same time, they turn on another protein system called mTORC1 that helps the cell grow.
When cells are stretched or pushed, a protein called BAG3 grabs onto two other proteins (TSC1/TSC2) that normally slow down protein production. This lets the cell make more proteins, as if it’s hitting the gas pedal.
When a cell gets stretched and its internal scaffolding gets damaged, it needs to turn off a specific molecular brake (mTORC1) right where the damage happened to start cleaning up the mess — otherwise, it won’t begin its self-repair process.
A protein called BAG3 acts like a magnet to grab another protein called TSC1, and together they help move a team of proteins to special cable-like structures in cells when those cells are stretched or pulled.
When cells get stretched or squeezed, a protein called BAG3 helps the cell clean up damaged parts and make new proteins at the same time, keeping everything balanced and working properly.
This study didn’t have enough people and didn’t hide who was taking what, so we can’t really say if taking creatine before or after the gym is better—it’s just too uncertain.