Researchers studied whether adding protein supplements to exercise training could help stroke patients improve their heart and lung fitness faster. They followed 114 stroke patients for 10 weeks, with some getting protein shakes and others getting a similar-tasting placebo drink while both groups did aerobic exercise. Both groups improved their fitness equally well, suggesting that protein supplements didn’t provide extra benefits beyond what exercise alone accomplished. However, the protein group did lose slightly more fat and showed small improvements in physical tasks, so protein may still have some minor benefits worth exploring further.

The Quick Take

  • What they studied: Whether drinking protein supplements while doing aerobic exercise helps stroke patients improve their heart and lung fitness better than exercise alone
  • Who participated: 114 adults who had a stroke (average age 57 years, 30% women) from four hospitals. All participants could walk and were at least several months past their stroke.
  • Key finding: Both the protein group and the placebo group improved their fitness by about the same amount after 10 weeks of exercise training. The protein group lost slightly more body fat and showed tiny improvements in physical tasks, but these differences were very small.
  • What it means for you: If you’re recovering from a stroke, doing regular aerobic exercise is what matters most for improving fitness. Adding expensive protein supplements probably won’t give you extra benefits, though they may help slightly with fat loss. Talk to your doctor about what’s best for your situation.

The Research Details

This was a high-quality study called a randomized controlled trial, which is the gold standard for testing whether something actually works. Researchers divided 114 stroke patients into two groups randomly—like flipping a coin to decide who got what. One group received protein supplements while the other got a placebo (a fake drink that tasted similar but had no protein). Neither the participants nor the people measuring their fitness knew who was getting the real protein, which helps prevent bias. Both groups did the same exercise program: 30 supervised aerobic training sessions over 10 weeks at four different hospitals. The researchers measured everyone’s fitness, body composition, and physical abilities at the start, after 11 weeks, and again at 20 weeks.

This study design is important because it shows what actually happens when you add protein to exercise, not just what we might guess. By comparing protein to a placebo drink (instead of comparing it to nothing), researchers could see if protein provides real extra benefits beyond the placebo effect. Having multiple hospitals involved and blinding both participants and assessors makes the results more trustworthy and harder to argue with.

This study has several strengths: it was randomized (reducing bias), blinded (participants didn’t know what they were getting), and 87% of participants completed it (good follow-up rate). The study was published in a respected medical journal. However, the sample size of 114 is moderate—larger studies might find different results. The study only lasted 10-20 weeks, so we don’t know about longer-term effects.

What the Results Show

The main finding was that both groups improved their peak oxygen consumption (a key measure of heart and lung fitness) by about the same small amount—1.7 mL/kg/min in the protein group versus 1.6 mL/kg/min in the placebo group. This difference of 0.1 was so tiny that it could easily be due to chance. In other words, the protein supplement didn’t help people’s fitness improve any faster than the placebo did. Both groups showed improvements in most measures of fitness and physical ability, which shows that the exercise program itself was beneficial for everyone. At the 11-week mark, the protein group had slightly less body fat (about 0.6 kg or 1.3 pounds less), which was a small but measurable difference. At 20 weeks, the protein group showed a slightly larger improvement in physical performance tasks (0.7 points on a scale), though this was also a very small difference.

Besides the main fitness measure, researchers looked at several other outcomes. Both groups improved their ability to do physical tasks like walking and getting up from a chair. The protein group showed a small advantage in one test of physical performance (the Short Physical Performance Battery), improving by 0.7 points more than the placebo group. The protein group also lost slightly more fat mass at 11 weeks. However, there were no significant differences between groups in lean muscle mass, balance, or how quickly people could get up and walk.

Previous research suggested that protein supplements might help muscles recover better after exercise and prevent muscle loss. This study’s results suggest that when people are doing regular aerobic exercise, the exercise itself is powerful enough that adding protein doesn’t provide major extra benefits. The small improvements in fat loss and physical performance tasks hint that protein might have minor benefits, but they’re not large enough to be considered clinically important. This finding is somewhat surprising and suggests that the benefits of protein supplements may be smaller than previously thought for stroke patients doing aerobic training.

Several limitations should be considered: The study only lasted 10-20 weeks, so we don’t know if protein benefits might appear over longer periods. The study didn’t measure participants’ normal protein intake before the study, so some people might have already been eating plenty of protein. The sample size of 114 is moderate—a larger study might detect small benefits that this one missed. Most participants were relatively young (average age 57) and could walk, so results might not apply to older stroke patients or those with more severe disabilities. The study didn’t look at different doses of protein, so we don’t know if more protein might help.

The Bottom Line

For stroke patients doing aerobic exercise training: Focus on doing the exercise regularly, as that’s what provides the main fitness benefits (moderate to high confidence). Adding protein supplements probably won’t significantly boost your fitness gains beyond what exercise alone provides (moderate confidence). Protein supplements may provide very small benefits for fat loss and physical tasks, but these are minor (low to moderate confidence). Eating adequate protein through regular food is likely sufficient—you don’t necessarily need expensive supplements (moderate confidence). Discuss your individual needs with your doctor or dietitian, especially if you have concerns about muscle loss or nutrition.

This research is most relevant to adults recovering from stroke who are doing or considering aerobic exercise training. It’s especially useful for people wondering if they should buy expensive protein supplements. Healthcare providers working with stroke patients should know that protein supplements don’t significantly enhance fitness gains from exercise. People with very low protein intake might still benefit from ensuring adequate protein, but this study doesn’t address that question. This research is less relevant to people with other conditions or those not doing regular exercise training.

Fitness improvements from aerobic exercise typically appear within 2-4 weeks, with more noticeable changes by 8-10 weeks. This study measured changes at 11 weeks and found that both groups improved similarly. If you start aerobic training, expect gradual improvements over weeks and months, not days. The small additional benefits of protein (if any) would likely take similar timeframes to appear.

Want to Apply This Research?

  • Track weekly aerobic exercise sessions completed (target: 3 sessions per week) and monitor perceived energy levels and physical task ability (like climbing stairs or walking distance) every 2 weeks using a simple 1-10 scale.
  • Commit to attending supervised aerobic exercise sessions regularly (3 times per week) rather than spending money on protein supplements. If using the app, log each exercise session and note improvements in daily activities like walking, balance, or stair climbing.
  • Use the app to track exercise consistency over 8-12 weeks and monitor physical performance improvements through simple tests like timing how long it takes to walk a certain distance or how many stairs you can climb. Compare your progress every 4 weeks rather than daily, since fitness changes happen gradually.

This research summary is for educational purposes only and should not replace professional medical advice. Stroke recovery is individual, and what works for one person may not work for another. Before starting any new exercise program or making significant dietary changes, especially if you’ve had a stroke, consult with your doctor, physical therapist, or registered dietitian. They can assess your specific situation and provide personalized recommendations. This study shows that protein supplements don’t significantly enhance fitness gains from exercise in stroke patients, but individual needs may vary based on your overall health, nutrition status, and recovery goals.