As difficult as it may seem, there are some simple and effective ways to stay fit after age 50, 60, or 70! These five simple tips can help you get (and stay) fit.

Lift Weights

Weight lifting may be the single best way for older women to maintain overall fitness and stop the slow creeping fat gain. Building strength with weight training is possible at any age, and some studies show women in their 70's building significant muscle by lifting weights 2 to 3 times per week.

Walk Regularly

Walking has consistently been shown to improve cardiovascular fitness, help keep weight under control, and improve mood in those who maintain a regular walking routine. Any aerobic exercise (cycling, jogging, swimming) is great for maintaining lower levels of body fat and improving flexibility and overall body tone, but after age 50, walking has some advantages. The risk of injury is extremely low, so almost every woman can get out and start walking right away.

Walking can be done in most weather, there is no special equipment required. Perhaps the biggest benefit to walking is that it's useful. Walking for errands, to give your pet exercise, to socialize, or to get out in the fresh air are all added benefits of using a walking routine to maintain fitness. Combining walking with weight training and you will have a simple and effective way to get and stay, in shape after age 50.

Incorporate High-Intensity Interval Training (HIIT)

Interval training is a great way to improve overall fitness. It's fast and effective, but can be challenging. To get the benefits of interval training and minimize the risk, start slowly and stop when you are winded. For example, if you are out walking, increase your pace for 30 seconds, and then return to your regular pace. Repeat this 30-second burst once every 5 minutes. Continue until you've completed five, 30-second bursts.

As the days and weeks go by, you may find that you want to jog during that 30-second interval. The beauty of interval training is that you are in control of the effort and the number of reps. If you are already in great shape, you can add some high-intensity interval training and kick it up a notch. When you start intervals, always pay attention to any warning signs that you are overdoing it.

Perform Core Exercises

As we age and become less active, core strength is often one of the first things to suffer. Poor core strength can lead to a domino effect of other physical aches and pains due to poor body mechanics and poor alignment. Sore backs, hips, knees, and necks can often be traced back to poor core strength.

The core muscles include more than just the abs, so it's important to consistently perform a balanced core strength workout. Do the quick core workout (above) 3 to 4 times each week to maintain your core strength and stability.

Other great ways to maintain your core muscles are to perform simple body-weight exercises that force the core to contract as you stabilize your body.

Eat Enough Protein

Many older women aren't getting enough protein to maintain muscle mass. Protein is the major building block of the body, and because it isn't stored, it needs to be replenished regularly. Protein can be either complete (those containing 8 essential amino acids) or incomplete (lacking ​essential amino acids). Complete proteins are found in most animal sources such as meat, fish, and eggs while incomplete proteins are generally found in vegetables, fruit, and nuts.

Vegetarian athletes often struggle to get adequate protein if they don't pay careful attention to the way they combine food sources. If you aren't getting enough protein, it may be difficult to build or maintain muscle. If you are a vegetarian, it's even more important for you to learn how to get enough of this essential nutrient.

Getting, and staying, in shape after 50, 60, or 70 is possible, but it does require consistent movement and a bit of knowledge to get the most out of your activity.