How much of your portfolio should be invested in stocks in pre-retirement and in early retirement?

The stock market has been extremely volatile in past few weeks. How much volatility can you tolerate on the verge of retirement?
Investors getting ready to retire should have no more than 60% of their portfolios in stocks, writes John Coumarianos, a former Morningstar analyst. A simulation showed that a person retiring in 2000 with $500,000 saved and withdrawing 4% annually would have $424,000 left in 2018 at 60% stocks, $508,000 at 30% stocks, and less than $200,000 left if fully invested in stocks.
Other analyses suggest that pre- and early retirees should have no more than 30-40% invested in stocks. Keep in mind that we are in the longest bull market in history. That doesn't mean a bear market is around the corner but... what if it is? Could you stand to lose (at least on paper and in the short run) up to 50% of your stock portfolio? especially if you have no guaranteed pension?
Time to review your asset allocation and recognize that your tolerance for risk is not as high as you think it is.