求解getting up early is good for your health中为何getting要用现在分词?

1、划分句子成分有助于理解句子结构和意义：
【Getting up early 主语】【is good for 谓语】【your health宾语】
2、【Getting up early】这是【动名词做主语】 .例如：
Seeing is believing.
Meeting an old friend after so many years' departure is really a pleasant moment.
祝你开心如意!