When people spend time in the intensive care unit (ICU), their muscles can become weaker. Researchers followed 42 patients after they left the ICU to see how their muscles changed over the next few weeks. They used ultrasound (the same technology used during pregnancy) to measure muscle size and tested how strong patients were. The study found that most patients’ muscles stayed about the same size, but some groups—especially women and people who didn’t eat enough—lost more muscle. The good news is that patients’ strength and ability to move around improved over time. This research suggests that paying attention to nutrition after ICU stays might help protect muscles during recovery.

The Quick Take

  • What they studied: How much muscle people lose after leaving the ICU and whether their strength comes back during recovery
  • Who participated: 42 adults who spent at least 3 days in the ICU for various medical or surgical reasons. Researchers measured them when they left the ICU and then every 3-5 days for up to 28 days
  • Key finding: Overall, the group didn’t lose much muscle mass after leaving the ICU, but women and people who ate very little lost more muscle than others. Strength and physical function improved for most patients over time
  • What it means for you: If you or a loved one is recovering from a serious ICU stay, getting enough nutrition appears important for protecting muscles. Women may need extra attention to nutrition during recovery. However, this is a small study, so talk with your doctor about your specific recovery plan

The Research Details

This was a prospective cohort study, which means researchers followed real patients forward in time to see what happened naturally, rather than randomly assigning them to different treatments. The 42 patients were measured starting the day they left the ICU. Researchers used ultrasound to measure the thickness of the thigh muscle (quadriceps), which is a reliable way to track muscle size without radiation. They also tested grip strength (how hard patients could squeeze), measured how much energy their bodies were burning, and assessed how well they could move and function. All these measurements were repeated every 3-5 days until patients went home from the hospital or for up to 28 days, whichever came first. This repeated measurement approach allowed researchers to see patterns of change over time rather than just comparing a starting point to an ending point.

This research approach is important because it captures real recovery patterns in actual ICU patients rather than studying muscles in a lab. Ultrasound is practical and safe, making it useful for hospitals. By measuring the same patients multiple times, researchers could see who recovered quickly and who struggled, and identify which factors (like nutrition or gender) might explain the differences. This type of real-world evidence helps doctors understand what actually happens during recovery and who might need extra support

This study has some strengths: it was planned in advance and registered officially, measurements were taken frequently to track changes accurately, and it included both muscle size and function assessments. However, the sample size of 42 patients is relatively small, which limits how much we can generalize the findings to all ICU patients. The study included mixed medical and surgical patients, which is realistic but also means different types of illness were included. The researchers used appropriate statistical methods to analyze the data. The main limitation is that this is exploratory research meant to generate ideas for future studies rather than provide definitive answers

What the Results Show

When looking at the entire group of 42 patients, muscle thickness showed only a small and barely statistically significant change over time. This means that on average, patients didn’t lose substantial muscle mass after leaving the ICU during the recovery period studied. However, this group-level finding masks important differences between individual patients. When researchers looked more carefully at who lost the most muscle, they found that certain patients were at higher risk. Women in the study lost more muscle thickness than men. Patients who had very low nutritional intake (eating very little) also experienced greater muscle loss. Patients who weighed less at the start also showed more muscle loss. These findings suggest that while the average patient maintained muscle reasonably well, vulnerable subgroups needed more support.

The good news came from measurements of physical function and strength. Hand grip strength improved over time, and patients’ ability to move and perform daily activities got better throughout the recovery period. This suggests that even if some muscle loss occurred, patients were regaining their ability to function. Female sex and longer ICU stays were identified as factors associated with slower physical recovery. This means women and patients who were critically ill for longer periods took longer to regain their strength and mobility, even though their muscle measurements weren’t dramatically different

Previous research has shown that muscle wasting is common during ICU stays, but less is known about what happens after discharge. This study adds to our understanding by showing that the period immediately after ICU discharge may not be the time of most dramatic muscle loss—that likely happens during the ICU stay itself. The finding that nutrition and gender affect recovery aligns with other research suggesting these are important factors in recovery from critical illness. However, the relatively preserved muscle mass in this study was somewhat surprising and suggests that early mobilization and care after ICU discharge may be helping prevent severe muscle loss

The study included only 42 patients, which is a small number for drawing broad conclusions. The patients were from a single center, so results may not apply everywhere. The study only followed patients for up to 28 days after ICU discharge, so we don’t know what happens with longer-term recovery. The researchers couldn’t randomly assign patients to different nutrition levels—they just observed what naturally happened—so we can’t be certain that poor nutrition caused the muscle loss versus being a marker of other problems. Some patients may have left the hospital before 28 days, creating gaps in the data. The study didn’t include detailed information about what patients ate, making it hard to know exactly how nutrition affected outcomes

The Bottom Line

Based on this research, ICU patients should prioritize eating adequate nutrition during recovery (moderate confidence). Women recovering from ICU stays should pay special attention to nutrition and physical rehabilitation (low to moderate confidence). Patients should engage in movement and physical activity as cleared by their medical team, as this appears to support recovery of strength and function (moderate confidence). These recommendations should be personalized with your healthcare team based on your specific condition and needs

This research is most relevant for people recovering from serious ICU stays, their families, and healthcare providers caring for ICU patients. It’s particularly important for women and people with poor appetites after critical illness. It may be less directly applicable to people recovering from minor surgeries or short hospital stays. If you’re planning for potential ICU care or supporting someone in recovery, discussing nutrition and rehabilitation strategies with the medical team is important

Based on this study, most improvements in strength and function appeared within the first 2-4 weeks after ICU discharge. However, full recovery typically takes much longer—often weeks to months depending on how long the ICU stay was and the severity of illness. Muscle recovery may continue beyond the 28-day period studied here. Individual timelines vary greatly, so patience and consistent effort with nutrition and movement are important

Want to Apply This Research?

  • Track daily protein intake (in grams) and daily physical activity minutes. Set a goal of 1.2-1.5 grams of protein per kilogram of body weight daily, and gradually increase activity as tolerated. Log these daily to identify patterns and ensure adequate nutrition during recovery
  • Use the app to set reminders for eating protein-rich meals and snacks at regular intervals throughout the day. Create a simple mobility goal (like a 5-minute walk) and gradually increase it. Share progress with your healthcare provider to adjust the plan if needed
  • Weekly review of average protein intake and activity levels. Track subjective strength improvements (can you do more than last week?) and energy levels. If protein intake drops below target or activity decreases, flag this to discuss with your doctor. Monitor for any signs of complications that would require medical attention

This research describes patterns observed in one small study of 42 ICU patients and should not replace personalized medical advice. Recovery from critical illness is complex and varies greatly between individuals. If you are recovering from an ICU stay or caring for someone who is, work closely with your healthcare team to develop a recovery plan tailored to your specific condition, medications, and medical history. This information is educational and not a substitute for professional medical diagnosis, treatment, or advice. Always consult with your doctor before making significant changes to nutrition, activity, or rehabilitation during recovery from critical illness.