According to Dow Theory, an uptrend is defined by a series of Higher Highs (HH) and Higher Lows (HL). A Higher High occurs when the price rallies above the previous swing high, showing stronger buying pressure and increasing demand. A Higher Low forms when the price pulls back but stays above the previous low, indicating that sellers are losing strength and buyers are stepping in earlier. This sequence of rising peaks and rising troughs confirms that market sentiment remains bullish and that the trend is intact. As long as price continues to make HHs and HLs, the uptrend is considered strong — and a break below a previous Higher Low would be an early signal of potential trend weakness or reversal.