However you define success, whether it's building a billion-dollar business or being an amazing parent, there's one factor that gives you a massive boost toward reaching your goals. A healthy brain helps you achieve whatever it is you want to achieve in life. And sadly, as we age, we all start to wonder if our memory, focus, and cognitive speed is beginning to decline. 

How can you tell if your brain is as sharp as it ever was? No doubt a psychologist could give you a battery of time-consuming assessments. Or, according to recent research out of the U.K., you could just try one simple physical test to see if your brain is healthy.  

The simplest way to test your cognitive performance

The findings come from an examination of data on the physical and mental health of nearly a half million adults over 40. Crunching the numbers, a team led by the University of Manchester's Joseph Firth found that the stronger an individual's handgrip, the healthier their brain appeared to be across a number of measures, from memory to focus to logical reasoning. 

"When taking multiple factors into account such as age, gender, bodyweight, and education, our study confirms that people who are stronger do indeed tend to have better functioning brains," Firth explained. "There is a clear connection between muscular strength and brain health."

This offers individuals looking for a simple way to monitor their mental health a clear sign to keep an eye on. "The results strongly suggest that grip strength is a solid indicator of one's mental health and could be used to identify problems before other symptoms become noticeable," a Harvard University blog post digging into the study claimed. 

Strengthen your muscles, strengthen your brain? 

But does that mean you can also strengthen your mental acuity by strengthening your muscles? Previous studies have suggested that weight training helps keep your brain young, so there is evidence that stronger muscles can lead to a stronger brain. But Firth insists more research is needed before scientists can draw any firm conclusions. 

"What we need now are more studies to test if we can actually make our brains healthier by doing things that make our muscles stronger -- such as weight training," he commented. 

Still, preliminary evidence does appear to point in that direction and a doctor-approved strength training program will certainly do your mental and physical health no harm. So if these results inspire you to add a little weightlifting to your routine, there's no need to wait for further evidence to roll in. 

The bottom line

The takeaway here is twofold. First, if you're looking for a quick and dirty but still informative way to keep track of your brain's health, you could do a lot worse than monitoring your grip strength. Entrepreneurs and other busy professionals often sacrifice physical activity to meet the demands of their work, but if Zoom calls and endless desk time start to impact your overall strength, chances are it's not just your muscles that are taking a hit but your brain function too. 

Which brings us to the second takeaway. This is approximately the one-millionth expert or study I've covered that indicates exercise is great for both your body and mind (see here, here, and here, for example). So why wait for your grip to weaken to get active? Finding time and motivation for exercise can sometimes be hard, but this is just one of a boatload of studies that show it's also totally worth it.